You do realize you're making a biased, hypocritical argument, right? When a Twi'lek Jedi wears a skimpy outfit it's cultural. When a Twi'lek dancer wears a skimpy outfit, she was forced to. :)

Anyway, let's just point out the truth in one part of your statement that I stand behind 100%: "there is usually a reason for it in the narrative or the lore (or both) ..." The game is no different. All these posts in Reddit referencing head-canon and you don't think the players might have a reason? Some bounty hunter dresses sexy because boobs make men stupid. Some Inquisitor has a scantily clad Mako because he treats her like a slave. Some Juggernaut's Vette is wearing a dancer outfit because she doesn't want him looking at other chicks. Some female Jedi is wearing a dancer outfit because they found it on the security key vendor and thought it was cool. My girlfriend dresses all her female toons skimpy just because she thinks they look hot (how dare she!)

I think the real argument is here is, "who cares?" It's digital cartoons. Who cares what the toons are wearing and why? Stop being so judgmental. Let people spend their money they way they want and dress the characters how they want.