Unless he'd rather have all of it for himself, and ends up robbing you/killing you and taking it from your body.
Pothead logic is soooo awesome man.
He's right though.
Several times on the metrolink in St. Louis (near where this robbery in the OP happened) I've turned what might have been a robbery into a discussion about weed and the drug war. I've (5'9 semi athletic white guy) have been surrounded by black teens talking about Mike Brown and brought up weed, that I like it, etc.. They end up changing their stance, talking about it, etc.
Not saying it will always work, but cannabis has many times been a universal equalizer in what might have been a hostile situation.
It's like no matter your color or race, nobody wants to rob or fuck with a fellow weed enthusiast. I can't rob a dude who'd smoke a blunt with me. Right?