You know describing him as a "drug addict" doesn't seem to be accurate. Based upon most of what I've read about his issues, I'd describe him as more as a severe alcoholic. Maybe I'm just parsing it, but if he's an alcoholic it would lend more credence to the idea that the league might be more willing to let him come back and play if only because it would help his recovery.
I would guess 95% of the league's players drink alcohol on a weekly basis. I'm also assuming that Gordon was on a zero tolerance alcohol DAILY testing program when he fell off the wagon last season. So it wasn't like he was found passed out on the bar. Just one beer would have violated him.
That doesn't mean I absolve him of that selfish decision. But since I have been exposed to the ravages of addiction in my family, I can empathize with the lack of rationality that comes with addiction. And while it seems to most people, who might not understand addiction, that it was unthinkable that he'd do it AGAIN, it just is what it is. Addiction, by definition, is a loss of control. Rationality has nothing to do it.