Family Matters

So there's something I've been struggling with a lot lately. I'm pretty sure you all know about my whole fun family, especially the man formerly known as my uncle. Okay, that was a little confusing. Just in case you don't remember or were never clear on the details, allow me a brief review.
1. My uncle (Steve) cheated on my aunt multiple times. She forgave him, but ultimately he divorced her and moved up to Washington state, where...
2. He met this divorced woman with two kids of her own who he brought to meet us in Abilene and...
3. Randomly married her in Vegas on their way home without telling any of us.
4. My family apparently doesn't deal with anything. We go with the idea that as long as you pretend everything is all right, nothing can possibly be wrong.
5. My dad's side of the family has the thrilling Aunt Bonnie, who is controlling and mean. Everything she does is right and anyone who disagrees with her is wrong. Oh, and health and wealth gospel big time.
6. Aunt Bonnie and Uncle Scott are in the processs of adopting a baby which is bad because they're over 50, have a VERY skewed vision of Christianity, and are in general very disagreeable people who feel that everyone should venerate them.
Anyway, my immediate family is really small and so we spend a lot of time together. A lot. And while I love being with my mom's parents, who all of you know are amazing people, I'm sick of hearing how great of a mom Bonnie is (in her own view point), how wonderful Steve's new kids are and how much fun it is to have new grandchildren, how cute baby Jonathan is, and how perfect our family is. Now, I try to just politely listen so as not to upset anybody because I don't want to hurt any of my grandparents' feelings. They are, after all, old (especially mom's parents, who are both around 80). But I'm also going nuts trying to be polite to people who are so screwed up. I'm tired of listening to people gloating about how amazing they are when they're actually doing stuff that's wrong or stupid.
So here's my question: How obligated am I to protect people's feelings? How much craziness do I put up with before I say that I have reached the bounds of fillial piety? When can I say what's on my mind? (And don't worry, I'll censor my thoughts when I finally share them.) What's a nice way of saying that I want nothing to do with the man who willfully tore apart my family or to the woman who assumes that she's so much better of a mom than mine just because here husband has been raising a little boy that she only sees 3 hours a day for the past 6 months? (BTW, Scott had a nice little rant the other night about how Bonnie knows nothing about parenting and how sick he is of her telling him what to do since he's the one that actually takes care of the kid all day every day.) Do I just keep my thoughts to myself? or is it appropriate to say some of what's on my mind?
HELP!!!
Oh, and I miss you all. This would be so much easier to discuss if you guys were all here in the same room with me.