Well, you guessed incorrectly. I don't have a problem with a beer or two, had one last night. I don't do it often but that is my choice. If I felt like a single beer was bad I would not drink it. Marijuana is a drug. It posses serious health concerns. If we truly care about these kids as athletes then we will want them 100% physically and mentally fit both for football and for life. I am guessing you have never been around teenagers who have been using marijuana for several years.
As for being able to drink and serve in the military, that is a common comparison. So one can drive at 16, why not make everything at age 16? I have taught 12 year olds to shoot a firearm, what does that have to do with drinking?