You can no doubt drink yourself dumb, there is even a German expression for it ("Er hat sich blöd gesoffen."). And some people can't handle an alcohol dosage healthwise that has no impact (or not one as severe) on others. And there are studies according to which, while African-Americans drink less alcohol than whites across the board, they handle alcoholism (when and where it does occur) worse. Judging from my time in Africa, I would also say that black men aren't as alcohol-hardened as white men.
And all those rock star deaths due to pancreatic cancer, there wasn't a single one of them that I heard of who was not a heavy drinker at a certain time in his life (Jon Lord, Trevor Bolder, John Wetton, David Bowie - he first drank heavily before the US tours got him on coke, he would see the aftereffects of both) - just like the severe coke users died of heart attacks decades later (even after they had kicked the habit), Robert Palmer, Rick Parfitt, John Entwistle ... Some damage you do to yourself cannot be repaired.