This is actually super alien to Tom. Is it the general principle of the thing? He finds people ... behaving offensively, in some unspecified way ... to superior officers intrinsically offensive? That's kind of weird though since he just himself picked a fight with a superior officer. Maybe he didn't realize and didn't want to be embarrassed by backtracking? Maybe he considers what he did to be technically not offensive in some way, or less so in a way that makes it not a big deal (for all Tom knows, B'elanna spit in Tuvok's face, so maybe he's right)?
Alternatively, maybe he just really likes Tuvok for some reason? Tuvok presumably had to approve him joining security, so they probably met? Maybe they hit it off?
Alternatively, maybe he doesn't respect B'elanna for some reason he's not articulating, and is mentally adjusting her rank downward to the point where he's allowed to pick a fight with her under his definition of proper behaviour? Maybe because she's an alien? A woman?
Alternatively, maybe he hasn't quite realized he's not a captain?
Well, probably the best bet is to figure out what he's pissed off about. It seems better than "so are you a huge hypocrite or what?".
"What did she do to Tuvok?"