He has lost his temper needlessly in the past and acknowledged it as something to work on and from my limited perspective it looks like he has.
I don't see this particular rant in question to be a personal attack though. Personally, I don't see a macho, jockish atmosphere to the Linux kernel community either. Also, I'm also not particularly concerned whether an environment is cultivated where anyone feels they can contribute. People contribute to the kernel out of need as well as want.
To directly address the part of the comment about otherwise capable contributors (and the Sarah Sharp example): There's multiple kinds of capability. Technical capability isn't the be-all, end-all in this industry. In fact, I think most of us would say that soft-skills are what differentiate high levels of success in this career. If a company's management culture disagrees with you, then you aren't capable of contributing in that atmosphere.
It's not a matter of either party being to blame but a matter of fit between two parties working towards a mutual goal. I don't think it's remotely fair to say that it's solely Linus's responsibility to facilitate a culture where anyone can feel comfortable contributing. Especially with a project as fundamentally necessary where people will have to contribute, regardless of the culture. If someone's incompatibility with the culture trumps their need to work in it, then yes, they should part ways and that should be perfectly okay.
The same applies to personal relationships, marriages, etc. I think it's good to step back from things from time to time and realize that, ultimately, you're dealing with people and they're not always going to value what you value and they're not always going to give you what you want.
Linus is BDFL. That's all you need to know in four letters. Why are people trying to give ultimatums to God? Seems pointless.