Jews have their synagogues segregated like muslims do and i've seen this myself.
Christian nuns have to cover their their heads which is the same concept as the hijab. And if they do not cover their heads then they should shave their heads.
The concept is more or less the same.
No it is not. Far from it. You talk only of Nuns. Firstly not all Nuns cover their heads. Secondly Catholics do not allow women clergy not for the reasons Islam gives but because Jesus was male! No Christian denomination, not a single one, does not allow women to preach because it will "distract" men. In fact most Christian denominations allow female clergy. And the arguments, as I have said numerous times, have nothing to do with distract. Primarily they deal with Jesus being male and the priest being a representative of Christ.
Referring to Nuns you are talking about something completely different.
In addition you speak of Judaism? Every denomination of Judaism ordains women as Rabbis and cantors, except the Orthodox. That is the majority. In addition it is only in Orthodox synagogues that the genders are separated.
As for churches, men and women do sit together. In nearly all denominations.
So, aside from one denomination of Judaism, a tiny minority of Christian denominations, and Islam, everyone else always women to be clergy and are not distracted by their female preachers.