Jeez, calm down. "Citation needed" generates no more obligation than the original unsupported opinion did. Would you blow up the same way about "I disagree"?

The fact is, most opinions about what language somebody else ought to write their next library in are worth about what they cost to post.

Another is that, trendiness notwithstanding, Rust right now is best suited for a library few people will need. That may change in five or ten years. It might well not.