My understanding is that adding muscle mass helps a batter hit the ball further and increase his chances of hitting home runs (HR).
The basic exercise to accomplish this is weight lifting. Brian Downing did this starting around 1979 and it helped him add muscle mass and increase his HR hitting, although he set no records even though he looked different. No one got mad him.
Barry Bonds wanted to add muscle mass. Apparently he both lifted weights and took steroids. He looked a lot different and set HR records. Everybody outside San Francisco got mad at him.
Bonds could have added muscle mass the old fashion way as Brian Downing had done. Bonds chose to do it the new way as Mark McGwire and Sammy Sosa had done. They made themselves look very different and they set HR records. Most people liked what they were doing at first then got mad at them later.
How much of a difference do the steroids make, especially for a player as great as Bonds already was? Could Bonds have set HR records without the steroids, maybe even without the weight lifting alone?
There must be a practical limit for muscle mass on a human frame. I'm guessing that Babe Ruth, Jimmie Foxx, Mickey Mantle, players like that could not bulk up and hit the ball much further than they already did. I'm guessing that they did not need to lift weights much less take steroids. If you can already hit the ball 480-500 feet, you're already at a practical limit for how far a ball can be hit. But I'm just guessing.
This is not a moral judgement, just a baseball one. Ruth, Foxx and Mantle all abused their bodies with alcohol, which should have decreased their effectiveness over time. Bonds at least abused his body to increase his effectiveness.
So what if Bonds had bulked up simply by lifting weights? Would we be mad at him?