Also, there weren't strong-arm lefthanded relievers coming in to face Ruth like Bonds has had to endure. Most pitchers back then pitched 7-9 innings each game. That gave Ruth an opportunity to hit against pitchers who were tiring more towards the end of a game.
Different time, different game. Ruth and Bonds, great players for their eras.
A pretty definitive look at things statistically between what Bonds did this season and what McGwire did in '98:
Bonds vs. McGwire: Who had it easier?
I've always like Rob Neyer at ESPN. This article does nothing to diminish that.