Even if someone's values seem wrong by every objective measure, their life is their own, and unless they are infringing on the equal rights of others, it isn't our place to interfere by force.

"Hey, smoking tobacco/weed/crack/whatever is bad for your health, and I advise against doing it."

"If you smoke tobacco/weed/crack/whatever in your own home, I will send people with guns to kidnap you, steal your property, and murder you if you resist."

Bit of a difference.