Either get a baby sitter, or stay home. Don't complain that THEIR idea of a good time doesn't much up with what is convenient/desirable for YOU.

It's their own party that they are spending their own money on. And you want to tell them how to run it?

We got no details, but what if it was a fancy formal type affair? You don't think some snotty nose kids would ruin that whole vibe?

For whatever reason, they want to party with adults. They don't want no damn kids running around, screaming, crying, fussing, causing distractions. That's the environment they want to create for their event. It ain't about you.