The main reason is because:-
30 Tell the believing men to lower their gaze and be modest. That is purer for them. Lo! Allah is Aware of what they do.
31 And tell the believing women to lower their gaze and be modest, and to display of their adornment only that which is apparent, and to draw their veils over their bosoms, and not to reveal their adornment save to their own husbands or fathers or husbands' fathers, or their sons or their husbands' sons, or their brothers or their brothers' sons or sisters' sons, or their women, or their slaves, or male attendants who lack vigor, or children who know naught of women's nakedness. And let them not stamp their feet so as to reveal what they hide of their adornment. And turn unto Allah together, O believers, in order that ye may succeed.
32 And marry such of you as are solitary and the pious of your slaves and maid servants. If they be poor; Allah will enrich them of His bounty. Allah is of ample means, Aware.
- Qur'an The Light -
Now, you could argue that these "activists" are not believers, and there should not be any laws about hijab in a majority Muslim country. Others would disagree.
I think that the problem is all over the world. It has become increasingly global, and the west has exported its values all over.
It is not just Muslim countries that have "a bone to pick" with the west. They are more often than not, stuck in the middle, between Russia and China on the one hand, and US and Western Europe on the other.