Two concepts....we KNOW of....and dangerous..
Did the doctor say we know everything about mj? No.
What did the doctor mean by dangerous?
Did by not dangerous did he mean is was not immediately toxic? Or not explosive or corrosive? Is it dangerous if a bus driver is using it?
Much more is known about mj now and it is best to use more information when assessing mjs risks and benefits.
Agreed - the doctor's comments were relevant to the question of why marijuana was criminalized.