Harm? Really?
And writing “I’m sure” after your post tells me you haven’t done any research before chastising someone. He’s a valuable contributing member of this site and you seem to have a personal issue with something he’s done. I assure you the amount of valuable information he’s posted is vast and you should bury the animosity and move on.
His problem is that he can't stay within his bubble and realize he has no expertise outside of it. Nothing wrong with what he does to his car but it would be bad advice for someone that's in a different bubble.
His bubble is no better than anyone elses and he doesn't realize that.