Mizael opens his mouth to say he doesn't know why it is or isn't, that's why he's asking, but then promptly shuts it again and just looks genuinely confused. It's clear they'll just be going in circles that way. So instead he closes his eyes for a moment to think of another way to frame his confusion.

"...Isn't like being a god of...hands? Or hair? Not very useful, but you have other skills that are..."

Somewhere between Takuto glancing at his crotch and his decision that it was some human thing and the images in the temple, he did actually figure out what they're talking about here. Or rather, he's making an educated guess based on what vague knowledge of humans he seems to have.