"Well, yeah, they do it, but they tend to get kind of mad if you talk about it in polite company." Taako raises an eyebrow at 9S; defensive much?

Shit, wait, did humans make this guy? That would explain a whole lot. Dammit, he's talking shit about humans to one of their kids, basically. It's not enough to stop him, or even slow his roll, but he does realize it, and is exasperated by it, on some level.