In my experience very few if any SSPX priests (that's where I go) can guide young people in matters of MJ, alcohol, self-abuse, pornography and pre-marital relations, because they have no personal experience whatsoever.
This is a very dangerous and stupid statement. You're almost denying the vocational graces and holy inspirations that priests have, from the Holy Ghost, to guide those
young people of good will. You need to step off your soap box.
If you have not smoked pot you can't know anything but what you read. If you have friends who smoke pot, that is one way to learn about the effects by seeing them and how they live. Do you have any experience with relatives and friends who smoke pot?
Yep, I have known many people over the years who smoke. I currently know a few lawyers who use it to unwind, instead of alcohol. In my experience, some kids go overboard, some don't. Some turn into hippies, some don't. Some grow out of it and some don't. It depends on the person.