Not surprisingly, it comes from baseball think-tank, Bill James, as noted in Joe Posnanski's blog.
In 36 words:
1) Baseball allowed a situation to develop in which it was in the self-interest of players to use steroids.
2) Now we are very angry with people because they did what the system rewarded them for doing.
Hopefully, this can put an effective end on the Alex Rodriguez talk (obviously, wishful thinking on my part).