It's not really any different, no. I suppose the aesthetic analogue would be trying to generalise from my own preferences to what I thought other people would like. There would be a difference between my own tastes, and how I was defining "good". Mapping back to ethics, there's a distinction between my own preferences (i.e. the predictors of my actual actions), and my sense of how the best world might be defined if I gave myself no more stake in deciding things than anyone else.

There's no objective reason for caring about the latter more than the former. I just do, and other people seem to care a lot too.