> What if I want to grow a plant and smoke it?

That's allowed: again, reasonable and obvious restrictions.

> and my cost/benefit analysis for me personally is that I gain more from smoking than I lose?

All well and good, but that goes out the window when you sell Tobacco.

> I wasn't advocating for smoking to defend capitalism, and think you appear disingenuous for suggesting that

It's not disingenuous IMO, it's obvious. Gambling is addictive, okay so let me draw a comparison to an already existing addictive substance that we've successfully regulated. Oh, look, tobacco!

We managed to do that and not be communist. And everyone is all well and good and we're pretty much all over it. Turns out, only wins! So it can be done, was kind of my point.