I'm not a fan of kids either. But hey...guess what? Not being willing to put on your big boy pants and suck it up for an hour is the very definition of "being a selfish asshole".
The fact that the first thing you talk about is how those kids are "going to be the focus of the occasion" (your words), shows that what you lack isn't "enthusiasm about catching up with someone". What you lack is basic human empathy.
You realize that most functional adults have the ability to focus on more than one person at a time right? Just because mom is taking a moment to wipe some spit off of babies face doesn't mean she's not listening to the person on the other side of the table. And the idea of that seems to be exactly the OP's deal (and yours, apparently)
It's not the "doesn't like kids" aspect that makes them the asshole. Hell, I don't like kids. It's the "I'm competing for that person's 100% attention" when I "grace them with my presence" mentality of the post that makes them the asshole.