Just imagine any other "crime" with similar penalties to which politicians and others can fess up and not suffer a loss of reputation. It would cover a broad range, given that marijuana growing or distribution can result in a multiyear or even life sentence. "I robbed a couple convenience stores when I was young and wild." "Broke into a few houses but never armed or while anyone was home." "Yeah, I did a fair amount of shoplifting when I was a teen."

Also, try to imagine a class of crime other than drug crime of which if all the perpetrators were caught society wouldn't be better off. If all the pot smokers were "caught" simultaneously the US would come to a standstill.

Another thought experiment- if pot is so bad, why is the worst thing that can happen as a result of its use is being caught by the cops? Millions of people have used pot and gone to have successful, high-profile careers. How many would be doing so now if they had a criminal record?

The "war on drugs" is nothing more than a culture war. You might want to protect your kids, but considering that the worst thing can happen as a result of pot use is a run-in with the cops, maybe your first priority should be preventing their arrest for doing something relatively harmless to them and completely harmless to others.