I think this is essentially a tribal, not a logical issue. A nuanced view is not welcome on these kinds of issues, you're either with us or against us.
You can be against the prohibition of marijuana while also thinking it's a bad idea to smoke it all the time, or at all. Laws don't have to match your personal beliefs.
I agree thet debate is polarised. But I sympathise with the irritation caused by the focus on poor quality evidence linking cannabis to psychosis when the widespread harms of alcohol and tobacco are basically ignored.
You can be against the prohibition of marijuana while also thinking it's a bad idea to smoke it all the time, or at all. Laws don't have to match your personal beliefs.