[prospero]

I was only saying that Zed does more good than harm. In fact, I don't see him doing any harm (except possibly, as you point out, to himself) unless you're saying that we suffer by not having an easy-going Zed to talk with late into the evening.

This isn't a workplace; you're not forced to interact with Zed. Either you decide it's worth the potential grief, or you decide it's not. I don't understand what your personal stake in his behavior is.