Of course, that is our society's prerogative.
That said, I can remember back in the 1960's when people went to prison for the possession of a single joint. I personally am glad I never went to prison for such an infraction.
“If, as a society, the U.S. decided to enforce the law like Singapore, that would make the U.S. a very different country.”
Well, yes. Pick your poison:
1. sacrifice some of your freedoms in exchange for a “cleaner” and healthier society, or
2. Keep your permissive “freedoms” to do drugs and end up like Portland or San Francisco.