I wasn't referring to copying that I would do myself, but copying that other crates would do.

That is, if a crate only needs a little bit from a little dependency, then copying it into their crate can make everyone else's life easier (obviously taking licensing into consideration when doing so).

In short, the context here was the bytes crate, which is fairly tiny. If rust is going to insist on not including the bytes crate, or a copy of it, in the standard library, then I would hope others that consume it would consider embedding a snapshot of it into their own crate for their own, private use so that I don't have to worry about it.

I'm well aware there's a fine line here, hence my reference to the Go proverb.