Theory fighting is the act of taking facts about a game, character, and/or match-up and extrapolating them out to make a statement that may or may not check with the actual facts of how said game/character/match-up works in reality. Your assertion was that Haku-Men is automatically dangerous to zoners because of his meter gain. Check your post again versus the definition, which, honestly, you should know, since you claim to play fighters. Does it fit? Absolutely. Anyway, theory fighting's generally okay; even the best will lapse into it sometimes. qwerty makes the point, though, that you are theory fighting without any base at all, as you have not played BlazBlue for any extended period of time. The point I'll now make is that you seem to think that you are more correct about a character than someone who has played that character since his release. That's not theory fighting, that's plain old hubris.
Also, qwerty absolutely did not miss your point. He addressed it very clearly. Read his post again. It addresses your assertion that Haku-Men's meter gain makes him dangerous to zoners. I promise you, it's there.