I'm not trying to make a problem. Do you not believe that denominationalism and the endless schisming in Christianity is problematic for the faith? I didn't make that happen, and I'm certainly not the first person to point it out.
Christians are divided on:
Is Jesus God? Is God a Trinity? Is God unchanging? Which books belong in the Bible? Is the Bible inerrant? Is the Bible the sole and final infallible source of doctrinal teaching? Is faith alone necessary for salvation? Is baptism necessary for salvation? What is the proper method for baptism? What is the nature of communion/the Eucharist? Is it literally Christ's body, spiritually his body, or completely metaphorical/symbolic? Who is eligible to partake? Can salvation be lost? Are some people eternally going to hell? Is hell conscious torment or just death? Should women be allowed to be pastors/priests? Should LGBT people be allowed to be pastors/priests? Should churches perform same sex weddings? Is divorce a sin? In all circumstances? Is abortion a sin? In all circumstances? What will the nature of the end times be like?
I could go on. Y'all are divided every way from Sunday, to the point that many of the above questions are considered dividing lines among the faithful between who's a "true" Christian and who isn't. The OP's inquiry is why that is.
OK. I don't see it as a problem. I am just trying to locate the OP and the purpose and direction.
Are there differences? Absolutely.
Couple of things we have to remember though, because it isn't as cut and dry as a first glance could make it.
For an example, God told the Jewish people in Jeremiah 4:4 Circumcise yourselves to the LORD, circumcise your hearts, you people of Judah and inhabitants of Jerusalem... gives it the understanding that there was more to being God's people than just the circumcision of the flesh.
In other words, there are many people who say "I'm a Christian" but the possibility is that they are Christian in name only. So that alone can create a problem for sure.... it sure did in the Jewish nation.
So most of the list that you mentioned is of no consequence (as far as division is concerned).
Take salvation and works. For those who believe in Eph 2:8-9 "For it is by grace you have been saved, through faith and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast" but they still will have works.
Someone who believes works are necessary, they will also have works. Will the two meet together? They will in fellowship--and still disagree as to what is necessary in salvation -- but not denying that both are saved since both exercise good works. (There are always exceptions)
The same with baptism. There are some who believe that it is the infant baptism that is necessary, sprinkling, dunking and then some will say that it is necessary for salvation and others no.
But when the two (or three) come together, all are baptized in some form or another and the fruit of their lives will give testimony of salvation. They will "break bread" together, and won't deny that the other is saved even though they were baptized differently. (There are always exceptions)
I can say that, because I have had fellowship and broken bread with the above. Even went to a Coptic service... (WOW, THAT was along service!
You can look at it this way, there are three bedroom 2 bath split plan, all bedrooms on the same side plan, all bedroom in three completely different areas plan... and everyone one likes their house. Different but not "wrong".
As long as the foundation is square you can have your house however you like it.
Like a body, many parts, they look different but still one body.
Now, that being said, there is still some truth to "some" division but it isn't as common as people think as they just use the old "there are so many denominations" as a mantra because it sounds good (I use to use it when I wasn't a believer in Jesus).
But like I said, with 2 billion followers it isn't like you are going to get all to live just like Jesus because people are still people. Even Jesus had one who betrayed him after the 70 left him.
In one retreat in Orlando, Florida, (as I had said before), we had Catholic Priests, Episcopalians, Baptists, Pentecostals, Methodists, Non-denominational, Church of God, Assemblies of God and a few more... we all broke bread together, prayed and worship. No one doubted the other's salvation because we all were in agreement with the foundation. Some of which are:
- Man needs a savior
- Jesus is the mediator
- Jesus was born of a virgin
- Jesus died and was raised again
- The Blood of Jesus cleanses.\\
And things like that. (Baptism wasn't mentioned nor was it a dividing factor, works wasn't mentioned nor was it a dividing factor
I could go on... but maybe you had a more specific question?