In theory, you're right. In reality people who don't care about legalization one way or the other need to be given an incentive to vote for legalization. It shouldn't be a criminal act to being with and it shouldn't be taxed, but if you want to end prohibition the reality is the only way to get enough public support is to tax it. Best of two evils.
Depends what you mean by "for". If you mean what's is the purpose, then the answer is an incentive to get people to vote in favor of prohibition. If you mean where does the money go, then I believe the answer is into the state general fund.
Yeah, I got it. Everything you said is 100% correct in a fantasy world where whatever is good and right is the law of the land. In the real world it doesn't work that way. If I've got to pay an unfair tax in order to insure I never go to jail unjustly, I'll take it. If you're holding out for a third option where prohibition ends without a tax then you're waiting for something that will never happen.