The catcher is not a leaning post

[BretMan]

Whether or not this is acceptable is probably best answered by the fact that, apparently, you have never seen it happen before. I'm willing to bet that you won't find a single umpire here who thinks that this is a good mechanic. We're pretty much taught to NEVER put our hands on a player for any reason.

This even goes beyond "being annoying to the catcher". In this day and age, you never know how somebody might construe an adult touching a youth or minor. It's best for it not to even be a possible issue. Keep your hands off!

It's something that you might see in some higher levels of baseball. The umpire might LIGHTLY touch the catcher's back. I've been told that this is to either gauge the umpire's distance from the catcher or to let him know when the catcher moves (like going way outside right before the pitch). I don't think that you need to touch the catcher to see either one of those things. And, I've been told that if the catcher complains, then the umpire should stop it.

Notice I said "lightly" touch the catcher. I don't get this whole lean against or push forward on the catcher thing. That's just weird. I would report this umpire to whoever assigns your games or registers umpires in your area. Hopefully, they would do something about it and inform him that it's not acceptable.