Chaotic evil if he has done so after the PCs have warned him that you can't kill sapient beings for food. As chaotic evil means "can't control violent impulses." Possibly either neutral or chaotic neutral otherwise as neutral means "go with flow," more-or-less, and chaotic neutral means "puts freedom of self first." But if the other PCs aren't doing anything about it, they're potentially evil or neutral as well.

Also, where's the angry mob?

You don't have to change the alignment on the sheet, mind you; there are so few instances in the rules where alignment matters and you can just say that "actual alignment" affects those things, not "character sheet alignment." Reward inspiration for following the written alignment of chaotic neutral.