I don't know where you work but at most--if not all--of my jobs this sort of internal discussion can be somewhat common when things get heated. We hurl epithets about outsiders when we get frustrated, and sometimes speak strongly not unlike what ESR said.

Would that kind of language/dialog be tolerated if it was directed at other people present or on the team? Or towards stakeholders? Of course not.

Of course, our discussions don't get immortalized on a public mailing list for every interested busybody to critique, and that does change the dynamic a bit...

I wouldn't say such a thing, I believe.

But I think if I was in charge and I had to police behaviour a warning would be my first reaction, rather than an immediate ban.

I mean, aren't we supposed to tell people when they're wrong first, and only resort to harsher means later?