Weed and booze aren't chemicals. I guess you can make the argument that there's some chemistry involved in making booze, but that's neither here nor there.
We're talking about performance enhancing drugs, which by all accounts I think the consensus is that neither of the two are.
One thing I do agree with is that the rules are what they are, and if you're dumb enough to get high and sacrifice your shot at the the Olympics, that's on you. Get your ***** together and lay off the pipe for a spell. It's not like it's crack.