I think it's 100% wrong. Alcohol is a drug, it in no way brings out the truth in a person's personality or somehow enables them to get across inner feelings they wouldn't otherwise be able to. When someone tells me a drunk mind speaks sober thoughts or other such nonsense, it sounds as ridiculous to me as if I said to you that the same is true of heroin or crystal meth. No one would ever agree with that right? Since drinking is such a widely acceptable vice to have though, everyone acts like it's somehow different from the others. None of these drugs allow a person to be themselves, they're just drugs and you'll only get further away from the person you actually are as you consume more of them.
I know so many great people who completely turn into someone else once they start drinking. Am I just to assume that they're assholes forever because they act like a complete piece of shit while intoxicated but never under any other circumstances? People are wired differently and drugs don't affect any two people the same exact way, the one thing I know for sure though is that consuming a drug will turn you into a different person. Maybe you're a great guy while sober and you're still a great guy while drunk, that's wonderful but it isn't as simple as Rogan is making it out to be with that statement. Consume an excessive amount of any recreational drug and you are no longer yourself, plain and simple.