Didn't Torvalds famously state that he named git after himself? I think he knows he's harsh, and just believes that it is necessary to get things done.
The problem with that is he wasn't getting his point across. He (and several other major contributors) laid down rules that the kernel should never cross. One is randomly breaking userspace for less than great reasons, especially here where the proposed changes gained nearly nothing in return for the change.
I don't think the manner of his response was quite warranted... but alas, it was effective in getting the importance of his point across.
I'd honestly be more concerned if he did this privately more often than publicly.