Oh, yeah? So why do most, if not all, businesses test for marijuana use, including the NFL? Do you know more than they do?
Because it is still a federal crime and the DEA has it listed as a Schedule 1 controlled substance. According to the DEA's own definition used to qualify for the schedule 1 list it shouldn't be.
Schedule I
Schedule I drugs, substances, or chemicals are defined as drugs with no currently accepted medical use and a high potential for abuse. Some examples of Schedule I drugs are:
heroin, lysergic acid diethylamide (LSD), marijuana (cannabis), 3,4-methylenedioxymethamphetamine (ecstasy), methaqualone, and peyote
There are plenty of known and proven medical uses for it. What they mean by accepted is accepted by big pharma since it hasn't been yet it is still listed. As more states legalize it for medicinal and recreational use it will most likely come off the list at some point. If big pharma can find away to monopolize it medicinally on a large enough scale you would see it become accepted overnight.