Just my opinion here, I know its easy to say in hindsight in the 21st century that the kiss was coersion and therefore 'rape'. You could probably say the same thing about Elaan (date rape) and Deela (coersion) and I'm not going to even comment on what Kirk did and Spock said in 'Enemy Within'.
In the 60s I think if the kiss were voluntary it would have not been allowed.
I think I read somewhere that the studio wanted two attempts of the kiss shot - one where they managed to resist and another where it happened so they could decide later whether to air it. Shatner said he deliberately muffed the non-kiss so the executives had no choice to use the kiss shot. I think everyone thought it was important at the time that the interracial kiss be shown.
It may look lame in our eyes now but it led the way. When Uhura kissed Spock in ST09 no-one batted an eyelid (well about the interspecies/racial thing anyway).
I agree that the women in TOS and even TNG were mostly there to be saved or admire the men in the series. So even though Uhura was mostly just 'answering hailing frequencies' of the 5 regular women characters in TOS and TNG she was the only one who was not in 'a caring profession' or a secretary