Being highly invested and preoccupied by an emotionally consuming mission tends to steal resources from other aspects of your emotional life.

One helpful thing to keep in mind as a retort-stopper is that you won't "win," you won't change anyone's mind, you won't change any votes, you won't make the atmosphere in the room any better, YOU won't feel any better.

First group impressions can mask a lot of individual variations in the members.

Your parents' views are, by current standards, out there. Getting in their faces about it would be needlessly disrespectful, but there's no reason for you to tiptoe through their delusional little terrarium as if you can't bend even one blade of grass.

Plan your own vacations when you want to, and plan a suitable combined vacation with this other family when you want to. If they freak out at your planning your own vacations as you see fit, then let them. Bowing to unreasonable demands because someone will make you pay emotionally if you don't is not a healthy option.

If the guests want to wrest the check away from the host, because the host is also the guest of honor, then the guest who volunteers has to cover the whole thing. A guest can't volunteer -all- of the guests to pay for the host/honoree.

There's nothing like a good family when you're really up a tree.