He wasn't nearly as good as McGuire. McGwire had a 5.2 WAR as a skinny rookie. HOF voters that vote for him probably subscribe to the "HOFer without steroids" theory. Sosa was a good, sometimes very good player who suddenly exploded into a superstar for 5-6 year period. Also I think those that vote for McGwire probably took the fact that he basically owned up to his steroid use, while Sosa still refuses to admit he did anything wrong. He lost all credibility to deny cheating when he 1) got caught with a corked bat, 2) explained in extremely broken english that he accidently grabbed a batting practice bat 3) used more extremely broken english to not incriminate himself while being questioned about steroid use in congress and 4) was named in a report as someone who tested positive for steroids. It's a stupid reason why, but I definitely think thats the general thought process. Also, the numbers show McGwire was clearly the superior player, although just looking at the numbers and nothing else they both have HOF worthy numbers.