Language matters quite a bit to those considering contributing. It also provides some context for expectations about performance and reliability thanks to language idioms, features and culture.
But the info is right on the linked page. Somehow I don't think people who haven't even followed the submission link aren't the ones to worry about yet for "potential contributor".
People do tend to see tools written in a systems language in another light than tools written in a glue language. Did you read it as "rust (not C)" or did you read it as "rust (not Python)"?
i used to look down on languages other than C, considering programs written in C a better choice than eg. python. i have since reversed my stance because i realized that python is a lot more hackable. i haven't tried rust yet, but i would prefer it over C for sure. compared to python i won't know until i actually get familiar with rust.