What he's getting at is that since it's a miniboss, it's not subject to normal enemy naming rules.
EveryDayJoe45– "I can accept failure, everyone fails at something. But I can't accept not trying."--Michael Jordan TALK
And where are you getting that tidbit from? Manhandla (The Legend of Zelda), Gekko, Blaino (Link's Awakening), this, etc. are all like this... For these, plurals are usually kept for instances where the name itself is plural (Rolling Bones) or if they are always fought in multiple amounts (Dodongo Snakes).
This isn't getting through my thick skull. They're fought as two, right? Unless they appear as regular enemies later, which isn't in the article so I wouldn't know, then it would be two.
EveryDayJoe45– "You want the key, and I want you dead, so we can make this work"--Stalfos (The Legend of Neil) TALK
They are fought one at a time. Two seperate times throughout the Fire Temple.