<human>: Can you condense the text into three sentences or less?

I *HATE* part of my family. 

My uncle (mom's brother) has an awful family. He has a wife who is an idiot and kids who have had kids who have had kids who are all really stupid and rude. I cannot stand them. I like the rest of my family a lot but those people (let's call them the McDonalds) RUIN family gatherings for me. There's about 15 of them now. 

According to my mom, we can't exclude the McDonalds from family parties. I am expected to invite them to my birthday party (the whole family will be there and the McDonalds live in my town), to my wedding, to every single important event in my life. I don't want them there. I can't stand them.

Am I in the wrong here? Do I just have to suck it up because they're "family" (ugh)?

It's not that they ever did anything horrible, it's just that they're literally dumb and always seem to try to make you feel uncomfortable. I really, really, really do not like them. 
I dislike them so much that I'd rather have a smaller wedding, also excluding family that I love (so it's fair and no one feels singled out), than have the McDonalds there too.
<bot>: Can't stand my uncle's family. Do I have to suck it up and invite them to ALL THE THINGS because they're family?