Steroids are not only used to boost power. They can be used for any number of other things in the game that would never be traceable to a player's numbers in any way.
If everyone could be using, what does it accomplish to write threads about how a player *might* be using? There is nothing we can do about drug use in baseball -- and there is no reliable way to tell from mere numbers or pictures whether use has taken place. We are fooling ourselves if we think otherwise.