I gather, then, that you disagree with all those designated-driver PSAs. That you think public policy should be to encourage drunks to get behind the wheel and drive home (or not).
Adults engaging in legal drinking is not the same thing. The PSAs could apply to them. We’ve drawn the line at a specific age for drinking in our society. Since there’s no authority to “report” an adult drunk to, giving them a ride is a different situation. However I am pretty sure if you were trying to get your spouse to stop drinking, you wouldn’t constantly make yourself available as a ride to get them home from the bar, because that enables the behavior.