What are your arguments to the contrary?
You cheerfully point out that marijuana isn't as harmful as heroin, crack or crystal meth (and you're certainly correct about that), so you similarly should admit that it is addicts to those other illegal drugs that commit violent crimes to feed their habits and dealers of such other drugs that tend to commit murder to protect their turf. If you wish to legalize heroin, say so, but don't pretend that the supposed reduction in crime from the legalization of heroin (which I dispute, but which at least is possible) will occur if you legalize marijuana.
I suspect you're right that a marijuana dependency is less intense than for other drugs and thus less likely to lead to user crime. But the incentives and resources for dealers to commit crimes are exactly the same.
“If you want to argue that marijuana is no more harmful than alcohol or tobacco and should be legal, go ahead (although I’d argue to the contrary)”
“What are your arguments to the contrary?”
Even minor use of marijuana makes people more likely to yield to temptations and cravings instead of following the Ten Commandments; it takes a heck of a lot of alcohol to get a person to such state (and people can smoke as much tobacco as they please and it won’t affect their minds). Marijuana is a mind-altering drug, and we as a society have an interest in people having inhibitions and proper respect for morality. You may disagree with my values judgment, and you have every right to do so, but I still have a right to differentiate between a marijuana joint and a mug of beer. And if you notice that my argument could be extended to stand for the proposition that drinking alcohol until inebriation is as worthy of proscription as smoking a joint, then you’d be correct.
“I suspect you’re right that a marijuana dependency is less intense than for other drugs and thus less likely to lead to user crime. But the incentives and resources for dealers to commit crimes are exactly the same.”
One would think that the drug-legalization crowd would have matured enough that their arguments today weren’t the same as in the liner notes to a Cypress Hill album from 30 years ago. (I take that back, the argument has improved somewhat; legalization proponents no longer talk quite so much about how hemp is a really strong fabric that may be used for clothing and stuff ... so of course it should be good for smoking.)