Imagine if in hockey a defenseman falls down leading to a breakaway goal and we said, nah that’s an unearned goal. He doesn’t get credit for the goal and it doesn’t count against the goalies GAA. A defender in football makes a mistake leading to a big gain. We don’t credit the QB or the WR. It’s crazy. There’s literally no other place in sports this is done.
Sometimes defenders make unbelievable plays to save the pitchers bacon, sometimes they screw up and cost the pitcher. That's part of the game. For some reason, in this particular aspect, we try to unwind history and give the pitcher a pass.