I wouldn't vote for someone I knew used PEDs. The real problem here is the ASSUMPTION that all these guys used.
I cannot stand Bonds - have always hated him, and I'm confident he used. But I would vote for him if I had a ballot. Why? Because it has never been proven that he knowingly took a banned substance - and considering all the witch hunts, that's saying something. I'd also vote for Sosa.
Then you have guys who used Andro and other stuff that wasn't illegal when they played. You can't hold that against them now that it's banned if they didn't break any rules at the time they were using.
Bottom line: Speculation isn't enough. If you can't present 100%, conclusive proof a guy used, he should get a vote.