Does religion stop us to be open

I think it does for a lot of people. Those who adhere strongly to a religion have already decided what they believe, and many religious beliefs contain ideas that those who don't share your religion are somehow bad or wrong. We see people rejecting sound science, hating homosexuals, and otherwise forming very strong opinions based of reasons that simply don't hold up to any rational scrutiny. If one tries to show many of these people facts and studies which contradict their beliefs, they get very upset and sometimes even violent, which just makes them look more insane. IF you have an opinion that differs with something in the Bible, many will chime in with "But GOD says... thereby instantly closing their mind to any other options. So yes, it very obviously does close people's minds, regardless of any lofty phrases about being nice to people.