Well, then let me be a little bit clearer. Leaving a nice comment on main saying you disagree with closing something is helpful, as long as it doesn't derail into a lengthy debate (at that time, move to meta). That way, people in the close vote queue can see why it shouldn't be closed and vote to leave open (and if you vote to leave open there, leaving a comment afterwards is also nice to see!).
But poking fun of other communities in chat is a bit... less appropriate ;) You still want those people to feel okay dropping in here, and you want people that visit both sites to not feel torn bet…