I suspect, for them, true Trek (tm) is skin deep. White people. Ships that resemble the familiar. Pew pew. Men are men and women are there to be toyed with and wear short skirts. Only a few foreigners allowed, serving at the pleasure of a mainly white, quasi (and not so quasi) militaristic organization, often with little power (Spock notwithstanding -- he was an alien but also clearly very humanoid and of an acceptable shade).
Also, not for nothin', but apart from the velour uniforms, the costumes just plain
do not fit. This is even on slender people. They are all, without exception, cut too small in the arm holes. This is why they bunch up at the armpits and shoulders.
What kills me is, this could've been an easy and fairly cheap fix. Buy a few black turtlenecks, the undershirts they were using will do – just sacrifice one or two to the cause – and hire a local tailor/seamstress (hell, even the sewing people at a local dry cleaner can do it, and they don't have to be particularly talented) to add gores (see for definition:
http://www.renaissancetailor.com/demos_goresgussets.htm) to the underarms and the problem is solved. It also neatly solves a potential other issue, that of successfully camouflaging any sweat stains as it's Georgia and it can get hot there, particularly in case you need to turn down/off the a/c in order to improve sound quality.