I've seen this being done with me numerous times as well. In general, it would nice if we could say "hi", "good game" or "thanks for the game", but I find nothing really wrong with disabling chat. I have found many very abusive people who write whatever they wish.
Furthermore, the guys don't know each other, so it is understandable they do not wanna talk and have distractions. Although I would discourage such an attitude of disabling chat, I think it is perfectly fine.
I did it due to morons trying to put me off by just typing in the chatbox constantly ie holding down the keyboard etc.
Other people moaning and whinging, crying and generally being bad behaved. So just disabled.