I'm going to expose my mom as a racist bigot to all of her liberal dinner guests
Is there a reason you're being so mean to your mom?
Yes, they're not actually my real parents and they're not really my real family.
I know you're upset, but you shouldn't just expose your parents at dinner. You're just gonna create a big fight.
It's what they deserve. They've been living a lie and all of their friends deserve to know the truth about my mom.
Even if they are racist, perhaps you can talk to them about it instead of ambushing them at a dinner party. It seems like this could cause a permanent rift between you and your parents. I really encourage you to handle this privately and not in front of your parents' friends.