Why just communities be forced to accept everyone? Or even be nice?
When in a group of friends we can often times not “be nice” however because we know each other, we understand it comes from a place of love.
Perhaps it’s a military background thing, but exclusivity has its benefits.
Because opinion is transient and can be changed on a whim, unless what is part of the identity of the person (physical apparence, religion and other cor values). Being exclusive only reduce cohesiveness.