Never lost a bomber is not relevant in today's terms. The loss rates were way down when the Red Tails covered the bombers. In WWII that was huge. Men invent stories to help them deal with the horrible situations they faced. Today we look at it from a pristine view. To me no losses vs few losses mean nothing, in terms of the bomber crews was what counted.
Its the same myth that a Tiger tank took five Shermans to kill it. Some took out many Shermans and were never put out of action. Others ran out of gas and were 'killed' several times over by Shermans making sure it was not a threat. FoW and perception, it happens