The Rust team puts a lot of effort into not gratuitously maligning anything, including a "competitor" language like C++: discussions of other languages try to be as factual as possible, and, Rust is very happy to adopt the good ideas of them (and of course acknowledge this), e.g. Rust's closures are modeled after C++11's lambdas.

As with anything, some people who like Rust might get a bit enthusiastic about discussing its benefits compared to other languages, but this is frowned upon and IME usually called out, especially in spaces with some sort of "official" Rust moderation presence.