I know that director Hal Sutherland was colorblind, but you'd think someone would notice this before it went on the air. I'm not certain of the process in the 1970s, but there are at least a few people who see those frames and not one of them thought to ask whether the Klingons should really be wearing pink?
~Topher, Killer of Threads
The animators may not have been familiar with the show and could only go by what the director told them. At that time, Star Trek had only been popular with young people. This was only three and a half years after the show went off the air so it hadn't become a cultural touchstone yet. This series was a kids' show and the characters were aliens so why would the animators argue about them wearing pink?
George Carlin: It's all bullsh-t and it's bad for ya.
Hal Sutherland had a type of color blindness that led to numerous color issues in the series. The art department tried to compensate for this, but sometimes color oddities still crept in, such as the pink spacecraft Traitor's Claw and the pink tribbles. (This isn't a joke--it's actually true.)
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Only stupid people believe in supernatural beings.