Agreement not to be nasty to people mostly protects people in a weak position. It's a long time since that has been Linus, so it's not surprising he's forgotten the merits of it.
Say 'Sarah Sharp' was hired by her company as a kernel developer. She knows that, if she makes a commit and Linus doesn't like it, he will write up what she has done like it was terrible (rather than slightly careless, or even just different from how he'd do it), and her boss will doubt her competence. Twice, three times, appears on google when he searches for her name... maybe she'll need a new employer...
So Sarah can either throw away her Linux expertise, and go work on BSD for way less money, or live in fear of Linus. Personally, I don't like living in fear. But presumably, she likes renting a house for her kids to live in. So there is nothing she can do except wake up in the night, unable to sleep until she checks the mailing list one last time.
I'm sure Linus doesn't care if she cusses at him. His worst case isn't homelessness.