How would you know that? Do a lot of dope in your day?
Or did you just hear that from someone else and accept that as gospel?
Personally, I've never smoked pot.
But, I have seen the desstructive nature of the drug in friends and family.
If you want to smoke, go right ahead - as long as you promise not to get behind the wheel of a car, a school bus, an airplane, etc. and you stay in your home - fine. But, I bet that's not going to happen. So, therefore, it becomes a problem for society.
IMHO.