To some extent, I measure how threatening they are by how dangerous they are to me as a bystander. I'd much rather see a major cigarette outlet near my house than an illegal marijuana distribution center. I can avoid most of the problems with a cigarette outlet by simply not going in. Not so much with the drug import hub.
We seem to have managed to neuter them pretty effectively by taxing cigarettes and making the public aware of just how bad they are for us. It looks like smoking is down about 60% in the US just due to minor regulation and social trends. Our approach with other drugs doesn't seem to be following the same trend.
Finally, measuring "evil" in absolute numbers is fraught with problems. If all we care about is number of dead rather than how they died and why, we'd be pounding on GM's door too. And of course, I don't think we Americans would be so unconcerned about the drug war if it was our country that they were turning into a failed state. Deaths notwithstanding, the total collapse of law and order in a democracy is something that should be talled on the "drug cartels are bad" side of the ledger, even if it's not our country they're doing it to. Duffel bags full of the heads of police officers and elected officials in some foreign country aren't a really big deal for us, so we tend to turn down the knob on "evil" when we assess it.