He was "caught redhanded" with a legal substance. Have you ever taken Ibuprofen? Basically the same thing. Ibuprofen is a steroid. It reduces inflammation. That is what androstenedione does.
Sosa never convinced Mac of anything. Sosa was more than happy to give an interview to anyone who wanted one. Mac never was comfortable giving interviews and just wanted to be left alone to do his job. Sosa was the darling of all the sportswriters because he gave them all the quotes they wanted, and they were continually upset with Mac because he wouldn't talk to them. Sosa also played up his underdog role during, with the bulk of the pressure going to Mac, who was expected to hit a home run every time he came to bat. Once again, going by my own criteria as to what makes a hero, McGwire set up a foundation in which he was the only one allowed to contribute. Since McGwire set up a foundation, and got good press on it, Sosa also set up a foundation. McGwire contributed $100,000 to Sosa's foundation, which was $100,000 more than Sosa contributed to his own foundation.
McGwire was treated well by the the fans during that home run race, but he has never been treated well by the sportswriters. And this past year they really had their chance to get back at him in the Hall of Fame voting.