Because of these two ways (and others) to cheat, people are crying that current ball player's stats have become moot and irrevelant. Sosa is no longer a home run hitter, but a home run receiver. It's treated as if Kenny Lofton used motorized roller blades each time he stole a base.
While I don't condone steroids or corking bats, I think that too much of a big deal is made about them and their contributions to the game. I don't think that there is a single home run that has been aided directly by the corking of a bat. Has a home run been hit with a corked bat? Most likely. But I also think that the home run would have been out with out the cork.
Strength is obviously a portion of hitting a home run. But it's not just strength. There is a whole anatomy to hitting that involves a variety of factors. The speed of the pitch. The spin of the pitched ball. The part of the bat which the batter hits. The angle at which the bat is tilted. Then, to a point, the strength with which the bat was swung. Not to mention the less physical aspects of seeing the pitch thats thrown and judging it correctly to be able to swing the bat so that it actually hits the pitch. After all of that is executed, there can be other factors, like wind and acts of God.
Strength only helps to a point, and it doesn't take too much strength to hit a home run. Pitchers can hit a home run. They don't hit them as often because they close their eyes and flail wildly at a pitch. Even though they're not strong and bulging with muscles the way Jim Thome is, they can pop one out, even if it is an accident. But if they studied the art of home runs (instead of practicing pitching) the way Bonds has, they could hit a fair number in a year. Of course, then they'd be no good as a pitcher and would find themselves languishing in left field.
Sure, there are a few home runs hit in a year that the additional strength may have helped, but not enough to taint numbers. Bonds is one of the best hitters of all time, whether or not he takes steroids. This year he has a batting average of .350. Last year he had a batting average of .341. Over the past four seasons he's hit over .300. You can't do that by just hitting home runs. You do that by being a good batter. Steroids would not have helped with any of those non-home run hits, of which there were many. And steroids would not have helped much in the hitting of those home runs, as argued above.