The pot from 20 years ago was probably less dangerous than alcohol at that time(I say "probably"). But today the THC level in marijuana is 30+ times the level of 20 years ago. There is more research showing that at those levels there is serious central nervous system sequelae happening from both short term and long term use. I think the decision to throw open the market in the states where the referendums passed was very short sighted. There should have been a lot more thought and control go into the decision. The level and potency of the THC in the products available to the public needed to be contolled and limited.
And it absolutely is a fact that increased supply and access of marijuana in these states will mean easier access to minors. I don't see how you can deny that.