The thing is Linus speaks volumes to people like Linus. And it just so happens that people like Linus are really good at writing the kind of software that goes in an operating system. Most of the criticism either comes from outside or from the type of people who feel they need to protect others from things that they themselves are able to handle. The latter is basically where ideas about censorship come from (I'm going to read this first to decide whether it's suitable for you to read).

Perhaps because so much of the world do not learn how to read French...

Or to put it another way, “it doesn’t really matter what you call a flower, it still smells just as good”

So I imagine its extremely unlikely that any early contributer could be turned off by a linus rant targeting them. They contributor loss would have to be based on the fact that the rants exist at all.

My suspicion is that very few qualified contributors are scared off by the existence of Linus's rants. Maybe if it targetted them, repeatedly, but otherwise its difficult to imagine this is a significant source of loss.

I think I saw a quote from Linus that this is a good filter for non-serious contributors, but it is an additional barrier for anyone who might want to get involved.