Hi @dave2000, I am that man. Sure, I've done illegal things, and I still do, but generally I avoid breaking the law.
I note that my respect for the law has increased with age. Probably due to encountering more accomplished lawbreakers and not wanting to be the guy who says, "Yes, but it's OK if I break that law because it's a stupid law." Also knowing people who, perhaps, had a problem at an airport or with the state police. I find the law to be a useful reality check.
I note your argument above has made this into a 0/1 proposition ("because they are illegal I won't take them").
But I believe it is more true to reality to look at it probabilistically, i.e., on a given Friday night, is it more or less likely that I'd be offered MMJ by a friend if it's legal in CA versus not legal in CA.
I think this thought experiment clarifies the argument that consumption increases when MJ is legalized. Indeed, for medical MJ specifically, I think that is the point.