I think what the Reason article is missing is a discussion of the impact that "the impression of steroid use" gives to baseball as a sport. After all, as entertainment "perception is reality," at least to a decent extent. I think that this is what Robert is getting at. It doesn't matter whether 90% or 5-7% of baseball players are using steroids or other enhancing drugs, what matters most to the baseball fan is the continuation of an enjoyable sport. If the perception of steroid use harms the future of the sport that is a terrible thing.
A good, if dated (2002) article covering this issue from the beginnings of the scandal can be found at the ESPN website.
I look forward to an exciting baseball season. Our local Angels have an amazing lineup this year and the 5-10 games I go to this season should be wonderful.