There was an interview with his agent on Radio 4 a couple of days ago, when his agent said that Dwain knew about the risk of a ban when he was taking performance-enhancing drugs, and knew that if he was caught, the BOA might be standing on rocky ground if they tried to enforce the ban, as it had never been challenged in the courts. With this in mind, he gambled that he wouldn't get caught, and if it would, he'd just appeal against the lifetime Olympic ban.
He gambled, he lost. This isn't a case of rehabilitation, this is a case of someone knowingly breaking the rules and having to suffer the consequences, such as they are in his industry.
I have to say that, PR-wise, his agent should be sacked. I have a lower opinion of Chambers now than I did before I heard his completely unsympathetic comments. This was not a man full of remorse, it was someone who thought they could get one over on the rules, and behaves like a petulent child when their plan does not work.