From the closing paragraph, I feel like he’s under the impression that Rust-advocating contributors are putting Rust’s interests (e.g. “legitimizing it” by getting it in the kernel) above the kernel itself.
Like with any emerging technology, early adopters become advocates because they’re convinced of the technology’s superiority. Once they organize into a community and get to know each other personally, then at least some of the motivation shifts: you want to see your friends succeed, you want to be part of a community that is making change, you want your early adoption to be “validated” by mainstream success, etc.
This can cloud technical judgment (not saying this is happening here, but if it were, it wouldn’t be surprising)