C is beautiful if you're standing on a motherboard staring up at it. If you think mostly in terms of how hardware works, C is a clean, powerful language.
"The language isn't truly high-level" isn't the whole argument; which would indeed be a straw man. That's the main part that's tied to the "most C++ programmers suck" argument, though. He thinks the "pseudo high-levelness" of C++ encourages sloppy programming.
Also there's another argument in there: Object-Orientation is overrated and often causes as many problems as it solves.
If Linus' experience with C developers is that they are better than C++ developers, it's probably because he is familiar with the qualities of good C developers.
"The language isn't truly high-level" isn't the whole argument; which would indeed be a straw man. That's the main part that's tied to the "most C++ programmers suck" argument, though. He thinks the "pseudo high-levelness" of C++ encourages sloppy programming.
Also there's another argument in there: Object-Orientation is overrated and often causes as many problems as it solves.