>>9433042He's wrong either way.
Historically, Hitmonlee has always been superior competitively due to it's higher attack stat and speed and always sat at least one tier higher than Hitmonchan. Hitmonlee has literally needed no real change and still surpassed Hitmonchan at every turn.
That said, I can't speak for anything gen 8 and on since I stopped playing competitively in gen 6 and dropped the games entirely in gen 7. Still even if Chan got better, that still makes Lee the superior Hitmon for at least 7 out of 9 gens I know.
