It is different than a party because of how participant driven it is combined with the scale. Sure you can see your friend's band at a house party, but most parties the size of Burning Man are entirely controlled by a single large entity, like Budweiser. When people talk about the fall of Burning Man they are really lamenting a trend to more centralized control and less participant interaction.
I've never been to a burn but I do agree with these diagnoses about the shortcomings of our society. I also make efforts in my community to confront these problems and it is a whole lot harder to change things than just going out and partying in the desert. I have no problem with people going out and partying but I don't think people should be claiming that it is much more than just that - a party.