Why does FM sound better than AM?

As a non radio engineer, reading this thread on HN is so fascinating because there are so many heated conflicting explanations for a common phenomenon in a well-established technology. I thought this simple question would be settled already. If such disagreement is possible even in an established "hard" science like this, then no wonder some people think everything is subjective.

This question is of course settled. However, it has more than one aspect and I am pretty sure there are also a lot of rather amateur people chiming in here ...

I am an EE, but in power electronics and not an RF engineer so I am a little bit hesitant to comment too much on it, but my understanding is that it mostly breaks down to two aspects:

1) noise interferes more with amplitude 2) the fidelity of the modulating signal in FM is higher (more bandwidth)

HN is not a meritocracy, anyone with an opinion can just chime in and then get upvoted by people who don't really understand what's going on.