The point I am making is that “might makes right, and right is this ideology that I have which involves various things that I claim are good” is still “might makes right”. Superman isn’t “in it for himself”, he’s in it for other people—which in fact is much worse.
Central examples of might makes right have many prominent aspects that are absent from what Superman does, even if in some technical sense it’s “might makes right”. Being in it for other people is one of those, but I mentioned several others.
Your term carries with it an inaccurate connotation.
(And if you didn’t intend that connotation, it doesn’t make sense as a criticism of Superman or a reason to call him evil anyway.)