the entire league has been set up to provide every incentive for players to use PEDs. the last thing the owners wanted back in the 90s was for players to stop using drugs. steroids revived the game; HGH allows their workers to stay off the disabled list; amphetamines allow them to play every night, 6 or 7 nights a week for 6-7 months out of the year, 162 total games plus spring and playoffs!
players can't become free agents until they're in their early 30s, exactly when their bodies start to break down (I say this from experience, and I'm sure it gets worse quickly in the late 30s and early 40s).
It's a moral choice whether or not to break the formal rules in your profession, and of course those who break the formal rules must be held accountable. but this is one of many issues where we focus on individual behavior instead of focusing on the system-level forces that drive behavior. in this case, players were operating in a system which was set up to give them every possible incentive to use PEDs. We get outraged when they respond to those incentives, but we rarely ask why the system was set up the way it was.
Who made money off of steroid use? what would have to change if all PEDs were strictly outlawed in MLB (or other sports)? would they have to scale back to 140 games or fewer? would rosters have to expand if DL stints last longer? would fans be interested in a league where the top HR hitters hit 30 a year, like the late 1970s? who would support those changes and who would oppose them? these are the questions we should be asking.