^^ I never noticed until just now that the document we see on screen refers to Spock as "half-Vulcan." I suppose a human-Vulcan hybrid, especially one serving in Starfleet, was a rarity and worth noting. In any case, no one at the time thought it was "racist."
Here's the insert shot of the file Mendez gives Kirk to look at in "The Menagerie" . . .
. . . and here are the magazine cover and car advertisement created for "Bread and Circuses." That's quite a bit of work for something that was seen on-screen for about 2 seconds.