Alcohol's a cross between not-that-bad and impossible to regulate.

We seem to be doing a better job of it than heroin.

Heroin is pretty fucking toxic.

Heroin is actually quite non-toxic. If your breathing is supported, you can survive pretty much any level of an opiate. It's not toxic to the liver, or pretty much any other organ.

We're talking a chemical with no benefit, that makes you literally need it all the time to even stay on a normal level once you're hooked

But it's worth mentioning that with dependence comes tolerance. When an opiate addict is maintained on the dose they need, they can carry out an otherwise normal life. Dr. William Halsted, for instance, had a brilliant surgical career and co-founded Johns Hopkins while maintaining himself on morphine. That doesn't happen with alcoholics.

if you cut it off completely after a certain point, you die from withdrawal.

That is simply not true. Unless your health is already seriously compromised it is not possible to die from opiate withdrawal.

Heroin will do it way easy; and the natural course of exposure is to tend towards that addiction, strongly. It's also much easier to overdose.

It's pretty easy to avoid an overdose, if you know what dose you're taking. Problem is, black market heroin is un-measured. Someone who could drop into a pharmacy and pick up a premeasured dose of heroin would be very unlikely to die from overdose.

This is a different problem than liquor, just like carrying a small rocket launcher is a different problem than carrying a 6 bullet revolver.

It's different, but not altogether worse. Heroin is easier to get addicted to, but the addiction is not as bad. Alcohol makes people more violent. Heroin makes people very mellow. It's easier to overdose on heroin, but you don't see the same sort of chronic toxicity you do with alcohol. You can't objectively claim that one is worse than another.