I think you need (at least) one exception to that rule. We have many people here whose first language is not English, and this is an English-only forum. For at least some of those people, an AI translation may give better clarity than their own attempt at writing in English.

So I would propose that, in the ideal world where we could perfectly enforce the rules that we chose, that the rule would be "AI for translation only". If it wrote your content, your comment is gone. If it translated content that you wrote, your comment is still welcome.