Well said there perrin, I couldn't agree more.
I would also say to the OP, that I don't seem to remember many (heated or otherwise) perlmonks discussions where the soul of an entire framework was in the balance.. Discussing for the sake of it is one thing, trying to decide the fate of a project is another. Also, the Catalyst discussing was taking place realtime, on IRC, thus it would have been a lot harder to preview content, consider, post only when really sure, etc, since by that time the moment is gone.. Thus heated discussions would have been a lot more so.
Civility and mediated discussion is definitely a plus, in my book, when things are at stake. Having them closed/private just means people can discuss properly.