So: extreme cases (both obesity and powerlifting) are not relevant when we're talking about population-wide averages. And relative weakness is also irrelevant (the original claim was solely about muscle mass -- if you want to talk about that being a bad metric, you're responding to the wrong comment).

You make one specific relevant claim: "obese people don't have more muscle." (Which belies everything I've read on the subject.) So, uh, why do you think that?