> Instead we're commenting on blog posts (instead of learning/making/doing).
> instead of learning
I don't know about your experiences with HN, but I find it to be one of the most efficient ways to learn about and keep up with the current state of the art, and commenting is a part of that. I usually get at least one good take-away for every four articles or comment threads - an extremely high ratio compared to any other web resource I know about. And for the craft we're in, learning and reasoning is doing.