Tyler Hamilton is just as big of a douchbag as Lance Armstrong. After years of denial he only admitted it after a second positive test and facing a potential lifetime ban made it more profitable to just admit it and try and profit off of bringing Armstrong down. He says he's doing it to clean up the sport but really he's just doing to make a buck of interviews and a book deal.
His acusations against Armstrong are probably true, but Armstrong is still justified to beat the crap out of him just like a criminal beats the crap out of his acomplice to turned him in for a plea deal.