I played hundreds of games online and I really don't remember to encounter someone to talk during the game! Especially for blitz. In my opinion, there is simply no sound reason to disable the chat if your opponent was not abusive. If your opponent is abusive, there is always the list of blocked players.
I think that here, on this site, I encountered this very "nice" behavior. If the game could be aborted, I aborted it immediately. Otherwise I played but making sure I added at the end the name of my opponent to my list of jerks.
It's like OTB your opponent would require you to play with your mouth sealed with tape!
As about disabling the chat, I find it very rude. Basically your opponent expects that he or she is playing a jerk. Otherwise he could have waited at least for you to say something in the chat and only then to disable it, if he thought that your comment was not appropriate.
I've especially checked - he didn't disable the chat when it was empty. Then I wrote "good luck" and he disabled it. So it means that "good luck" is something abusive...
Or that it simply reminded him that he forgot to disable chat right from the start.
Perhaps he just likes to play without any distraction. There's a myriad of reasons one might disable chat proactively -- try not to read too much into it.