Sheesh, what a stupid thing to say.

The only reason humans can deal with chocolate and not dogs or cats, if they were interested in it, is because our bodies can expell the stimulants before it does harm to us. Dogs and cats aren't able to do this, it stays in their systems a lot longer and so can do the damage. Eating a bit of chocolate each day isn't going to change that.

The best thing for people to do is keep all cocoa and chocolate meant for people well out of reach of their pets. It isn't difficult really to keep stuff like that in an upper cupboard where a pet can't get to it.