If it's any consolation, I figured that the author was using "Rust programmer" as a shorthand way to say "I know Rust best and that tends to be my point of comparison when learning other programming languages. But there's no particular loyalty there, and it's not like Rust is the only language I know. It's just the systems language that I already tend to think in".

I don't see any tribalism here, the original article addressed Rust programmers looking into C (so not currently C programmers).

It has always been like that in computing, starting on school playground about which 8 bit home computer each kid had.