The correct title should have been 'Mexico legalizes drug addictions', and I consider this a very, very good and important step for a country.
Why? Because there is a certain asymmetry in the drug scene.
On the one hand, you have those guys who are addicted. They buy small amounts of drugs to consume and, well, consume them. Usually, and especially for those harsher drugs, however, this addiction is physical, which -- at least to me -- qualifies as a sickness.
On the other hand, you have the professional drug dealers. They buy large amounts of drugs (much more than one could consume and not die) and sell drugs to other people. I consider this to be a nasty abuse of sick people (one might go as far and sort of compare it with stealing purses from people in wheelchairs, even though that might be a bit harsh).
Thus, mexico legalized a disease, while keeping abuse and organized criminality illegal, which seems like a good, correct step to me.