I'm so tired of repeatedly hearing this trite and ridiculously myopic response every time someone brings the subject up. No one is ignoring the realities of history here except you.
First of all, lets just state the fact that the principles of a government can be different from the reality of it. The two aren't mutually exclusive. It's as if by mentioning the worst affected groups you think you magically negate the foundational principles just because the implementation wasn't (and isn't) perfect. It's also not to say the system is theoretically perfect, because it's not, but to use such a logically weak strawman ("pining for a history which never existed") and not even expanding whatsoever is intellectually lazy at best.
"Come on, we can be against prohibition for practical reasons"
The foundational principles of American individualism is the greatest practical reason to be against prohibition. What the hell do you think enabled us to finally get rid of the shackles around those disaffected groups in the first place? It was the hard work that mostly Madison put into researching all the various forms of government, and the greatest political thinkers from around the world, that established a structure that although imperfect would be able to improve over time.
Before we continue this, my main question is whether you are American or not. I find that my approach to this subject needs variation for my friends across the pond. If you are, you need to brush up on your civics.