I get the impression that some people think of crates.io as purely a place for distributing arbitrary Rust free software, while others think it's also a place where people are building something like a community-developed "batteries included" standard library for Rust.

I think a fair amount of unpleasantness in recent years has come from this disconnect: some people think that by publishing on crates.io you're making some promises (that they might not assume simply for, say, having a repository on github).

To me, using an extremely generic name like 'base64' does suggest that you're in the second camp, and so that you might expect to have a conversation that feels more like "we're equals building this project together" than "I'm the maintainer and my judgement is all that matters".