The reason he rehabbed so fast is because it was just a move for publicity and the truth is Jones doesn't have a "problem" with drugs, he just got busted once.
I understand cocaine is much more dangerous and hardcore than like marijuana and it is hypocritical the way fighters have been punished far worse just for weed.
But two wrongs don't make a right. If Jon is a coke user, that's his business, just because the government tells you it is bad does not make it the truth; in the US people are still arrested daily for small amounts of weed, that doesn't mean it should be that way, it's just the corrupt laws and cultural narratives that have been put in place to help control the population.
It's actually no one's business but Jones it just so happens that he got busted for it during a pre-fight drug test. He is probably just a recreational user and not addicted.
It's his life.