Because people ARE NOT objective.
When they first play KOTOR, they are like "OMFG W0WZ0Rs!!!!"
Even if the sequel is better in EVERY way, people will still consider the reaction they got from the first experience of something unlike anything else, to the extension of that. Because of their previous experience with KOTOR, KOTOR 2 would have to be lightyears ahead of KOTOR 1 in order to illicit the same "w0w0w0w0w0w" effect. But because people did not get that effect, they compare the lesser "wow" with the "w0w0w0w0w0w" and draw the conclusion that the original is the best.
EDIT: Regarding head gear, if it doesn't look good, you don't need to wear it.