[A definite sore spot. He's had to deal with hunters and trappers and crazy psychos who want his dragon's head in the past years, and when it comes to Toothless' safety from humans, he can get defensive.]

Violence is a cycle. [It's an argument he'd had with his father a long time ago. They've killed hundreds of us, said Stoick, but we've killed thousands of them, said Hiccup.] I can't speak for anything else, but dragons, at least ones from the Barbaric Archipelago like Toothless, are just like any other wild animal. They defend themselves when threatened.