I recently beat the game, and I am really, really thankful to the larvae. Seriously; without their help, I don't think I could defeat Yog-Dzewa. xD
Without them, the fists could reach & kill me within a few turns, the larvae can act as a meatshield, forming a barrier to block, between me & Yog-Dzewa, against those two strong-as-hell Fists. I would be happy to get surrounded by those little bugs, as they can get those life-threatening fists away from me.
Additionally, those larvae don't really hurt much; I often dodge them with my Assassin, and when they do hit me, the damage is always zero. They seldom hit me over 10; never over 15.
So... why would the wiki suggest to "kill them before more are spawned" and "Do not let more than 7 Larvae spawn"? In my opinion, this will make your process in damaging the real boss a lot slower, and you lose the meat barrier advantage.
These larvae do not do anything. As you said they rarley damage you and when they do its like 5 damage. I've never used a "meat shield" since I normally go for the fists first, so I would not know how much advantage that would give you. Oh yeah congratulations on getting the Amulet of Yendor. ; D