could it also be, they find that certain religion to be fascinating and get involved in that religion? or find it spiritually good for them, and that is why they become a follower eventually?

People these days have no clue what there religion really stands for. Look at all the denominations. People take what they want from religion. I believe in a Divine power. Thats it. Everything else is just a system. Usually to establish power and wealth. Other then that, people use religion for different reasons, but really dont know what their doctrines represent. The English language is a big barrier to learning old text.

Christianity dominates involuntarily,because there is evidences in the Holy Bible.Then there is other multitudinous religions at that time or thereabouts,which likewise had evidences.So unbridled is people's oaths that they wish to be a follower of that religion,but there is an analogy-all religions are not malicious.So everyone can opt out a befitting religion,or not literally not to opt out any religions,as those occult powers is looming,or perchance pseudo.Yes,religions have barriers,and are not worthwhile to have faith in it superfluously.

But if a person without any religions will find himself lone and lost,hence he might opt out a religion.

I met a man like that once. He was preaching in the street about christianity, saying about how god saved him from his brain disease, how he was once an atheist and tried each and every religion, finding a cure in christianity after his wife fell ill also. I swear, if 'coincidence' wasn't in the dictionary, people would just outright refuse the existence of them.

There was also an indian fellow with him who maintained that science proves nothing and that the periodic table of elements came from god. He was pretty much ignored.