Because that would "infringe upon their rights".

I think the difference is that deaf people don't choose to be deaf, but us iPod/music listeners chose to use them. They want people to choose the best option available.

The trouble is, some people are too stupid to ride safely anyway, whether they're listening to an iPod or not -- but nobody blames the rider. So, if they just happen to be wearing earphones and have an accident, then golly, it must have been the music's fault, because nobody can be inherently stupid.