It didn't make Stiles' words any less true. Isaac could be easily cowed, the right combination of words and circumstances could easily push him into that headspace where he didn't care who was giving the orders, so long as someone was. Derek had worked hard to teach the other slaves how to speak to Isaac, just so they wouldn't take advantage of Isaac's submissive nature.
It still didn't matter. Because before Stiles had even realized he was there, he'd been praising Isaac for taking what he wanted. Which wasn't Derek.
He knew that ignoring Isaac's pose would hurt the younger werewolf, but he stepped back anyway.