MJ on its own has certainly ruined some people, especially daily users. I would argue, however, significantly less so than alcohol. It also has a much lower harm fact on others than alcohol.

MJ used more sparingly, and especially when used on someone with exposure to a psychedelic (not simultaneously but maybe the weekend after a trip)? Entirely different ballgame. It can awaken an internal symphony of inspiration and thinking.

Everything can be abused. Eat too much if anything and you will suffer. But when used appropriately, very magical experiences can be had that enable routes of thinking and problem solving that seem to come from out of this world.

In general, my recommendation to anyone is to try these things while simply meditating or hiking a safe & easy trail. Your mileage will vary but when done correctly, you will acquire otherworldly inspiration applicable towards your skilled professions and hobbies.

And if nothing else, even falling short of that result, this possibility should be enough for legality.

Parent's quote refers to the psychedelic DMT, not to mj.

Marijuana is very different from psychedelics in this regard.

To paraphrase Bill Hicks, if you think marijuana/drug use has never had a good effect on society, take all of your favorite music and throw it in the trash. All of the musicians recording that music were "reaaaaalllll fucking high".