As well as the correlation/causation problem...
From what I hear, cannabis on sale today is rather stronger than when I was young. That sounds bad to me. Curiously I see this as a pro-legalization arguement, if it were available in a shop I could select a mild flavour, rather than the skunk that the criminals grew, and is all that is on offer
I've heard that too but if you go to any dispensary you can get a gummy with an exact dosage of THC and CBD on the label. It's actually a much superior system now to backchannel dried flower.