So, while I don't dispute the emphasis on modesty, I do wonder why it clings to ancient fashion.
My answer would be different from the rest, I agree modesty can be defined differently and what some muslim may say about it could be what they personally feel about following the dress code, but the reason why we actually follow the dress code isn't modesty; it is because we submit to The One True God, Allah.
We believe that all knowledge, all goodness, all wisdom and all power belongs to He, and He recommends only the best for us, and that best is the most enjoyable , when we believe it to be the best since it is coming form the best. When we submit to that truth, our dress code not only brings us joy, it spreads a serenity over souls , a sense of re-assured self confidence which does not come from any garment , than that of modesty which is brought Not by dressing a certain way( it may be a symbol of modesty) but actually by submitting to the will of Allah.
It is only He who means the best for His creation in the most plausible way, and what he ordains as the best cannot be replaced, substantiated by any second bests which come from even a combined group of the most intellectual, sincere human minds. So, till now, you will find some girls who don't like wearing hijab, their problem is not modesty or decency, they probably just miss out on the depth and strength of their closeness to the Creator, in one way or the other, and following that dress code doesn't feel good to them, they see it as a burden, it is not an enjoyable experience for them .( they might even say that they feel close to Allah and feel that they don't require it as per their understanding, and say we're close enough without following this command already so no need to be, umm more close, (I think, could be wrong), but I think that the relationship with the creator is ever growing, it can never just stop, there's always room for more. )
And then you will see some who are willing to die for their right to wear it, since they are able to derive immense inspiration and closeness to Allah, and they will never ever trade it for anything in the whole wide world, because that joy, and that sense of being close to the creator is irreplaceable, unparalleled by any other feeling they know.
Take the hijab. It's gone from being an item of clothing to the symbol of Islamic womanhood. Certain (misguided) Western institution try to ban it, while certain (also misguided) Islamic nations mandate it. A lot of fuss for a piece of clothing, don't you think?
Like I said above, its not just a piece of clothing, its a source of bonding close to the Love of the Creator, by following what He says .( we all follow wishes of those who we love the most, even if they go against us sometimes, but in this case since we know that Allah only means the best for us so we have no doubt over this). So whenever we disobey His commands, it brings us great internal turmoil, great disturbance, lack of peace of mind, and our faith starts deteriorating and our relationship with the creator suffers a lot.
There are people who dress up that way for cultural reasons, and you will find them frequently changing attires whenever their cultural surroundings change, but people who dress that way for closeness to Allah, you will never see them shun their dress wherever they go, non muslims may be able to just label it as an identity symbol of muslim women, but in reality it is a lot more than that. ( I hope though that you know that muslim women dress that way only when they go out, or are in company of strange men, i.e men who are not related to them, the rest of the times, they can wear anything they like which is suitable)
Anyway, one of the explanations was that values don't change. I think that's obviously incorrect, as it should be. Society progresses, and Muslims are not immune.
Thats right, human values keep changing because Humans are not absolute. We all die, everything that we see around us has an expiry date. It is Only the Absolute truth which Never changes. An absolute truth that was always there, before we were, and after everything. Muslims submit to that absolute truth,ie the One-ness of Allah, all power all wisdom of the Creator and that truth binds us to our values. No amount of human progress can be bigger or better than the social progress that is described by Allah, we humans know some details of only a few civilizations, He knows the details of behaviors of ALL civilizations, he knows what goes on in our minds and how we behave the best.
So far as muslims are concerned, they have been told to wait for the day that this world is going to collapse, non msulims think that societies will always progress, muslims are told that progress isn't having a great house, a nice car, a beautiful family , a nice degree and etc, since many highly progressed societies have completely been wiped off the face of the Earth, the pyramids of egyt still amaze us with their architecture, but that civilization is gone, who would've thought they'd ever be wiped out, if they did, they'd atleast not make such humongous structures for themselves risking their lives.
Hence, our definitions of success, worldly progress is way beyond the material realms of the world. Allah says in the Quran (something like), that when the day of judgment will arrive upon you, the oldest man will be asked, so how much do you think ,was your stay on earth? and the person would say, about just a day? and a half probably, not more? Our definitions of success, are all tied to the life of the here after.
In christianity,( I wish to be corrected if I'm wrong) I was told that when things go alright according to the worldly fake standards of happiness, the Lord is happy with you, and when they do not, means that the lord is not happy with you, and that thought depresses unfortunate people where they convince themselves they no longer have to please a Lord who is so hard to please .
Islam does not subscribe to this concept. In Islam, this life is just a test, for the rich and for the poor, where all sorts of people are placed in different environments, with different resources, and we have to make the best of those resources that are available to us: all we have to do is make an effort. Allah says " I will not ask you for good results, that is upon me, I will just see how sincerely you made the effort".
Now can you describe any human system that functions on the purity of intentions and sincerity? None, they all want results, and failing to give a desired result not only discourages us, it may well make us feel very undesire-able by the society, and maybe cursed by your lord which causes a lot frustration ( if some other beliefs were to be followed).
So what I was really trying to say is, that when we are not happy/content with our inner selves, no amount of worldly progress can bring you a growing contentment, the way submission to Allah does, all that worldly happiness is temporary. How long does the joy of any thing that we really like usually lasts? not longer than we wish it to last. It is only the sense of finding the creator that overshadows all happiness, all sorrow, all worries and transcends all worldly happiness, there is just no match.
I know many people say oh we're happy enough we have a perfect life, perfect family and etc, but that concept of happiness is very non-inclusive of unfortunate people, who don't have good families, or any families at all and are poor and distressed. It is only Islam that includes people from all spheres of life into the fold of happiness by not placing the financial burden/social status classifications on them, but just by urging them to know more about God as it brings them happiness, no matter in which ever circumstances. ( that is not to say that they are to not to work and progress in the world, it is just to stress to not focus entirely on the worldly aspect of material happiness and in the long run missing out on the real one.)
Lastly, Allah also says,(something like in the Quran) That "I never reject a sincere prayer for true guidance, that is the right of man upon me." So whoever will seek guidance with a humble and sincere heart, he will find it.
Sorry it took a long explanation, but just couldn't stop midway