Yesterday I walked by the front sign of a local middle school. It read "KNIGHTS RULE!"
No they don't. Knights serve.
That's the whole point of knights in the chivalric sense -- not to mention the original meaning of the word [ knecht in the Old Frissian (and later Old High and Middle High German --- although in Old English it refers to a boy/young man -- of course back then that's what young men were -- servants].
Anyway, seeing that led me to a whole meditation on how weird language and symbols are.
So we have this whole tradition of schools and sports and mascots. And part of that tradition is what mascots are suitable or not [ferocious animals and various types of warriors are quite popular].
And then we have this whole slang usage of "rule." My guess is that the origin of the slang is consonant with the standard meaning of the word, that is, things rule because they impose their order on the field of play. But it's become more like a generic term meaning something is cool and the best.
The mascot thing and the slang term meet in what is actually a prosaic piece of discourse [every middle school thinks they rule (except of course most of the students who are having the most miserable time they will probably ever have in their entire lives)], but is also an oxymoron.