I think that it is natural for some religions to be partial to religions that have similar beliefs.  I don’t think there is anything wrong with that.  It is natural for people to gravitate toward those with which they have things in common.  Yet religions should also practice tolerance.

There is a difference between being impartial and being tolerant. By definition, a true believer in one faith cannot be impartial. But they can be tolerant, regardless of how fervent they are in their own faith. However, both Christianity and Islam have strong evangelical strains, meaning that many believers feel an imperative to spread the faith. This is very much in tension with any notion of tolerance.

I'm not sure how much illiteracy and education levels play into religious beliefs.  I think most of our beliefs are cultural or stem from our upbringing.  Perhaps a person who lacks access to the world outside of their own culture (maybe because of illiteracy or a lack of education) might be natural more bias toward the religion their culture favors than a person who has been exposed to other religions.  Personally, I think it is good to be exposed to other religions.  While I only follow the beliefs of one particular religion myself, I do find that I can understand other people and other cultures when I have knowledge of other religions.

Although I only agree with the precepts of one particular religion, I think we need to be impartial as far as allowing religious freedom and expression is concerned. That means I have to tolerate a lot of religious expression that I don't agree with, but I'm willing to do that because I know that if people don't it's a very short trip to intolerance and then persecution.

I think you are stating that you do not support "partiality" between different religions, but - as stated by post 3 - I don't understand what you are thinking of when you refer to "partiality." To be partial to something usually means you have a preference for one thing or belief over another.

What do you mean by "partiality between religions?"  Are you asking if we should prefer one to another?  Are you asking if there should be more inter-faith dialogue to improve relations?  It's not clear from your question.  Could you clarify?