I think it cheapens the accomplishment. Bonds' home run record will mean less to me than the seasons other players had who did not tank up.
If a substance is banned, and a player gets caught using it, he ought to go sit with Pete Rose as far as I'm concerned. Toss enough people out for it, and most won't risk using it.
I know that if I show up for work tomorrow under the influence of something I ain't supposed to be using, I'm out of a job. Why are these people any different? A few zeros at the end of an earnings statement does not justify this behavior.