I'm a criminal defense attorney who represents many, many people involved in some aspect of the illegal controlled substances trade (buyers and sellers). I have an immediate family member who is a recovering addict and extremely active in Narcotics Anonymous. And I have several friends who have experimented with illegal drugs in high school and college. Here's what I strongly believe:
1. Marijuana is far less dangerous than alcohol. I have never met or represented someone who got high on marijuana and became violent. I have never met someone who robbed or stole to feed their marijuana habit. Most people who smoke marijuana laugh, eat, and sleep.
2. Marijuana is far less damaging to the body than alcohol or tobacco. I have never met someone who died from a marijuana overdose (impossible) or from marijuana abuse (though lung cancer is a theoretical side effect, I think it is highly unlikely- no one smokes 2 packs a day of marijuana). I think athletes favor marijuana because you can smoke and wake up the next day and not be hung over. That's not to say driving stoned is ok. But there are very few deaths a year directly attributable to marijuana (I imagine there are a handful of marijuana-related car accidents causing deaths and a handful of cases of lung cancer caused by marijuana.) There are hundreds of thousands of deaths a year attributable to alcohol and tobacco.
3. Marijuana is not physically addictive. There is no withdrawal when you quit using marijuana. I have suffered major headaches and been extremely lethargic when I quit caffeine, but no one who quits using marijuana complains of any physical withdrawal. Lots of people use marijuana then quit because it's no longer worth the risk. Lots of white collar professionals. Trust me.
4. Marijuana is not a gateway drug. People who are willing to break the law to alter their state of consciousness are often willing to try other drugs, but I am confident there is no causal connection linking the use of marijuana to the use of other illegal substances. I know lots and lots of people who have used marijuana and never tried anything else. Good friends, other professionals, family members, etc.
5. None of the above applies to cocaine, crack, heroin, oxycontin, opanas, meth, etc. That stuff will cause you to pimp your daughter, rob your mother, and do many other horrible things to feed that habit. Most my clients who rob and steal do so to feed one of those drug habits. I don't see a lot of people involved in crimes related to LSD or other hallucinogens, so I won't offer an opinion on those drugs.
6. People that think marijuana users are just like other "druggies" are woefully ignorant of reality and do more harm than good. If you're told throughout your childhood that marijuana is just as bad as cocaine, then you try marijuana and realize it's largely harmless, what do you now think about trying cocaine?
7. Alcohol, like marijuana, relaxes people. Drinking a single glass of wine doesn't make someone an alcoholic just like occasionally smoking a joint doesn't make someone a "druggie". If people tell you they drink solely because they like the taste, they're probably lying to you or themselves. They like the way it makes them feel. Flavor is generally just a bonus.
8. Marijuana use by NFL prospects should not be ignored by GMs. If nothing else, it tells you the prospect is willing to jeopardize his future just to smoke marijuana. That means he's guilty of at least poor judgment and, all other things being equal, is at least a bit more of a risk than an identical player who doesn't try marijuana.