Certainly fundamentalism takes many forms. You can be a ‘fundamentalist’ anything. To say that all fundamentalists have a mental defect or are looking for an easy life would a huge generalization.
There is no doubt people feel safe with their own ‘kind’ and a sense of belonging and group acceptance is a powerful societal force, but I would argue that is not necessarily a good thing. It may be sometimes, but not all the time. Yes, it’s good to hang out with like minded people, but not all the time. I also remember someone saying to me when you’re inside the circle you can’t see whats going on, you have to step outside the circle and look in to see what is going on.
I think people should step outside their comfort zone. If you never step outside your comfort zone, (Not ‘you’ personally) you will find it much more difficult to put yourself in someone else’s shoes, or see things from anyone else’s perspective. Meaning, you’re understanding of the world around will be very limited. It also facilitates the formation of opinions based on little more than assumptions, leading to stereotyping which creates prejudice. People inside the ‘circle,’ whatever that ‘circle’ may be are often unaware of these effects because they are inside the ‘circle.’ Those on the ‘outside’ can see it quite clearly. People inside the ‘circle’ are often less open to new ideas, resistant to change and stay people stuck within a certain mindset.
There are people who can maintain their identity and culture and integrate. I’m not boasting but the Irish are particularly good at that. (Well, they are when they go abroad, they’re not so good at it at home.

) The Chinese are another example. The Chinese have been in Ireland for years and have maintained their identity while and the same time integrating exceedingly well. There are other ethnic minorities that just refuse to integrate and consequently, they tend to be unpopular which also leads to stereotyping and prejudice.