[professoretc]

I think it stems from Rust's emphasis on safety. The logic is, memory errors in other languages lead to people's passwords being stolen, bank accounts compromised, etc. Those are Bad Things. Ergo, programming in anything but Rust is morally wrong and makes you a bad person.

A similar thing happened in the Ruby community, I think. Ruby was advertised as a language that would "make you happy". Its fans talked about how much fun it was to program in Ruby. Thus, anyone suggesting programming in any other language was actively trying to make you unhappy and thus a bad person.

That kind of moralizing about a choice of programming language is naturally going to attract people who think in moral terms, so every conflict becomes a battle between Right and Wrong.