First off, I think it's super important to keep healthy boundaries with anyone, including and especially family, if the relationship is hurtful. I don't think family members should get a free pass to be hurtful.

That being said, I think there is something important about family, especially if there are differences. Choosing to maintain some level of closeness with your family often requires you to learn difficult relational skills, and I think generally that's a net benefit to society.

To be able to say "you have some really problematic patterns of thinking, and I can see that better than most because I grew up with you, but I'm not going to leave you - I'm going to love you and continue to prioritize our relationship so that we have someone we can depend on no matter what" is important.