Let's say there were no such thing as steroids, but you found out Barry Bonds were using Sudafed or other stimulants. Even if you technically concluded he was "cheating", do you think people would be up in arms about it and not letting him into the Hall of Fame? I seriously doubt it.
Or, as I mentioned earlier, if you found out Tom Brady or Peyton Manning took HGH while rehabbing their injuries, would you feel it would diminish their accompishments? That's basically what Andy Pettite did. I doubt that people would think of Manning/Brady as cheaters, but would call Pettite a cheater.
Like I said, I think the obsession with steroids comes down to the ick factor, and is more unique to sports where there's an obsession with individual records.
Willie Mays, Hank Aaron, and many stars of 60s and the 70s have admitted to using methamphetamines. The witch hunt with Bonds and others goes much deeper than records.