As others have said, while this looks exploitative to modern eyes it was in the context where having a women serve in the quasi-military context of Trek was almost absurdly progressive. At the time, NASA refused to contemplate putting women in space, despite the efforts of a shadow training programme (https://en.wikipedia.org/wiki/Mercury_13) - far more misogynistic.

Trek also featured an interracial kiss (not quite the first, but nearly) at a time when interracial marriage was still illegal in several states. It was very much the SJW show of its time.