Interesting. Had never thought of that. If that's the reason, it would be a rare case of fantasy trying to be closer to fair than actual football is. Normally it's the opposite (eg, guy runs for 60 yards and gets tackled at the one; fullback vultures the TD and gets credited with more fantasy points).
I remember watching a Lions game once where I had Stafford and he dropped a perfect ball into Megatron's breadbasket that would have almost certainly been a TD. Just as Johnson was getting his hands on it, he got hit by a DB, ball popped up in the air and was picked off. I remember thinking, "How is it possible that Stafford gets punished for that play and Johnson doesn't?"