I think we are speaking past each other due to definitions. I wouldn’t think “lean” is the same as “super low body fat”. I assumed the lean we were talking about was maybe 10-13%. Whereas super low would likely be in the sub-8%.
Maybe, but 13% is still well under what I would suspect is the bar for being correlated with negative health outcomes. Most sources seem to suggest that 18-20% is still a healthy level.