Addiction is when your body is missing the effect of something, and you crave it when you go without. Anything you eat, drink, or smoke regularly will change your body chemistry enough that you will suffer withdrawal symptoms if you are no longer receiving that effect. The extreme withdrawal that you are speaking of comes from prolonged excessive use, not from simply getting drunk regularly.
There are things you can become physically dependent on and there are things you can't become physically dependent on. It's not "all relative" and not all things require prolonged excessive use to become addicted to. Alcohol you can become physically dependent on, and suffer from withdrawal systems. Saying someone is addicted to pot is akin to saying someone is addicted to gambling. They're not, it's the endorphin release they've been conditioned to enjoy.
It's like mixing drugs that you shouldn't, it's not the one that kills you but your use of both together. Alcohol poisoning doesn't come from getting drunk, it comes from having too many toxins in your body for a prolonged period of time. The alcohol alone won't do this, because your body knows to flush itself of the toxins.
You can absolutely get alcohol poisoning merely from drinking a lot of alcohol. Now I'm not talking about a reasonable amount of alcohol, but then not everyone drinks in reasonable amounts. Your body will purge toxins, however heavy drinkers' bodies are more used to alcohol and get progressive better at retaining. Enough alcohol paced right will kill you.
Just like alcohol doesn't have the calories, did that go over your head?
Are we talking about the real world or are we being purely theoretical? Alcohol doesn't have calories(it probably does actually) but you aren't drinking pure rubbing alcohol to get drunk. To smoke a joint you don't have to, assuming you aren't making it into brownies.
Eating a bunch of cupcakes, like getting drunk and getting into a fight, is activity that's caused by a high/drunk person, not the responsibility of the drug. It's a person's personal responsibility what they do if they take any sort of mind altering substance.
No, what you are talking about is smoking a joint verses getting absolutely sh!tfaced regularly. You don't get alcohol poisoning or suffer withdrawal from simply getting drunk.
No, you were talking about getting stoned versus having a glass of red wine before bed.