Like many rules changes, it was made because after much thought it was decided the game was better off after the change. Card game rules always change over time and even more so in Redemption's case. The game we have today is much different and much better than the one we had 10 years ago. This specific change was made to decrease the power level of characters that were protected from discard and force players to make smarter choices. Back then if you had no good rescue options you could still throw a protected from discard Hero out with no backup and force the opponent to use resources to block it at no cost to the rescuer. Now, you have to decide if you have enough backup to risk attacking with your strong, but not invincible, Hero.
