Eh, humans kill each other all the time, they tend not to hold it against anyone.

[ Crowley shrugs faintly, though he's definitely judging you, Gabe. He hasn't killed a human in... well, possibly not ever. He's not that sort of demon. ]

I didn't know that. [ He glances at the roses again. ]

You gave the humans poetry fodder for millennia. Also, they created some varieties that don't have thorns.