I think the key to this is accepting the situation. Not necessarily trying to figure out WHY your extended family are like this but just accepting that they are and there's not really anything you can do about it.

I'll give you an example. I have spent a large part of the last few years trying to figure out my DSD. Trying to figure out why she behaves the way she does and how I can help her see the error of her ways. I've really driven myself bonkers about it. I feel much happier and peaceful now that I've accepted that I've really tried my best, I can't change her and we may never get along that well.

I think in your situation, I would probably have a word with the people who are making you feel the way you do and if that doesn't work, then you know that you've done what you can and then try to accept that they're dills.