He admitted to using deer antler spray. It's a banned substance.
This is funny on a few levels, because Singh has already destroyed his rep once from cheating. He's also a surly asshole who can't hold on to caddies because he hits golf balls for 10 hours a day, every day. I know the ad hominem isn't necessary, but he stinks, and I hate him.
Given the self-policing nature of golf, transgressions must be penalized in a Draconian fashion.