> A lot of language are doing fine using dots.

I have implemented one such language, and while it is indeed doing fine, the dots-everywhere syntax really does complicate name resolution. It only uses it because the distinction between two different operators would be lost on its intended less-technical audience. It is a (in my opinion unfortunate) tradeoff made for a specific reason.

And one thing those languages all (as far as I know) have in common is that they do not have Rust's macro system. It may well be impossible to implement that without a distinct operator.

I have no opinion as to whether that operator should be `::` or some other arbitrary symbol, but I believe that no matter what symbol they chose, someone would complain that it doesn't fit their personal taste. Can't please everybody.