I brought it up because Mayweather can't be the greatest fighter of all time unless he has beaten the best fighters.

Your points on how Mayweather couldn't fight Mosely are wrong though.

Okay they were both at Welter weight.

Shane Mosely fights Jose Luis Cruz.
Floyd Mayweather fights Sharmba Mitchell.

Guess what happens next for both Jose Luis Cruz and Sharmba Mitchell. Ohhhhh they fight each other why would that be?
Why because Floyd Mayweather and his team decided he wasn't good enough to fight Mosely.

Either way. they could of fought after the first Vargas fight