I would say yes in the sense that you can probably learn more by reading other peoples thoughts carefully than by jumping in to post your own thoughts. But what if your main goal is to prove to yourself and others how smart you are? Or to win approval from others by posting intelligent points?

The best would be to do both reading and posting, I think. But like anything else, if you are pursuing multiple goals simultaneously, one can expect that sooner or later those goals are likely to come into conflict with eachother.