Because when musicians play it is not really a serious competition is it. It is people creating art after all. Quite a difference. They say the whole cycling competitive thing is riddled with drugs.
But a better option is for that whole area to get straight and drug free and then the finishing times will still be exciting but maybe a second or two less overall. Who cares what the actual fastest time really is. It is the variables between the competitors that is much more important and exciting.
So Armstrong's times may have been slightly less which means others may have won those races.
(how often were things really close with other racers and their times? Did Armstrong always win by a huge margin? I am not that familiar) It does not matter if he is great or not he will be remembered for this now rather than before. He did make an amazing recovery from Cancer as well which was very impressive. Maybe the performance enhancing drugs had a part to play in that.