It’s saying that criticism must “assume competence” - that’s very different - and as a moderator I can twist any kind of criticism into a violation of this rule. And why do I have to assume competence anyway - shouldn’t the work stand on its own merits?
And let’s get something straight - “being a moron” is not equivalent to being incompetent (in an area of expertise). One is just name calling the other is a specific legitimate criticism.