Dressing down someone like that on a public mailing list is absolutely picking on them. It's not an argument, and is basically no different to the behaviour here.
a. Linus uses swear words. Steve Klabnik used none.
b. Linus provides substantive criticism. Even if you need flame-retardant underwear to hear it.
c. Linus never ever ridicules outsiders.
So what do the two have in common, again?
I loved the mauro thread because you're seeing Linus talking to an insider of an influential project and tell him that the relative outsider with no status is right. By doing it publicly he reinforces the culture of the kernel: we don't break user code. We are a meritocracy, and if you're wrong I will not be shy about letting you know.
He could do it with less profanity. But I heartily support his doing it so emphatically. Nobody else on lkml will brush something off as a userland bug for a year.
There are many ways to reinforce meritocracy, or reinforce a culture without telling people to shut the fuck up in all caps.
That's actually not true. His "security monkey" references towards other projects being an example.