It's clear from the very public, recurrent fallout from Linus's behavior that it is not a matter of camaraderie or simple outsider misunderstanding. I agree, context matters. It's precisely because of the context that this language is not tolerable. The LKML is not a private Slack channel for friends.
Absolutely, among friends, such talk is generally tolerated and isn't a sign of rudeness or disrespect. My friends and I do the same thing in private channels. But in public in a professional setting is not at all the place for that.
And this is the funny thing about it. Even the people he "explodes" on usually get a lot of friendly "stop" messages from him well before any inflammatory message comes out. Only real exceptions I can think of is that he will meet an insult with an insult. Which, ironically, can go a decent way to making everyone else feel safer in the environment.
Edit to add: I do want to quickly add that as much praise as I can offer Linus in this regard, Knuth really is on another level. I do not intend to compare them.
> My Australian friends will ...
There's a common thread here: if you already know for sure that someone has respect and/or affection for you, harsh language from them just reinforces that, precisely because talking that way to a stranger or acquaintance is hostile.
Talking about language without context is meaningless and so I try not to judge Linus off of a few publicly available emails. My Australian friends will refer to each other with language that is shocking to me as an American, but I acknowledge the context aound it and don't write them off as assholes because of it.