By your hyper political correct line of thought Vulcans are treated in a racist way until TFF and McCoy is the worst culprit.
LOL! McCoy WAS a racist. He was written than way on purpose. When he says, for instance, that the "Trogolodites are mentally inferior!" you're supposed to cringe. Didn't you? The problem is that the TNG/DS9/VOY crews were not supposed to be racist. We're not supposed to be appalled by them. We're supposed to just agree. That's racist writing as opposed to racist characterization.
And, other than the Fu Man Chu mustaches and shoe polish, how were TOS Klingons racist? Besides being part of an aggressive military what was the definable characteristic all Klingons had? Kor was practical and jovial, but sadistic. Kras was offish and schemeing. Kor was gruff and powerful, yet resonable. Koloth was light hearted and sniveling. Krug was cold and savage. Every Klingon in TUC was completely unique. There's not a lot here roping these guys all together. They're individuals and that's why they are memorable. I can't remember one Ferengi from another across several series. So, really, drama was sacrificed for the sake of simplicity. It's not "Hyper PCism", it's good writing.
Think about Balance of Terror for a second. Here we've got several people on the Enterprise trying to pigeon hole a whole race of people while on the BOP we've actually got no less than three different view points and personalities colliding between the Commander, Decius, and the Centurion. And this is the first time we ever SEE a Romulan. So much for the "dramatic necessity of simplification".