But that bit of context is outweighed by (a) her being specifically described as an Earth female, and (b) that the Talosians' M.O. was breeding pairs from the same species.
And that Spock was clearly intended to be the token alien at the point.
But the presence of umpteen human-looking species in the TOS universe does give us a bit of wiggle room if we want to make Pike's crew a bit more cosmopolitan, which may have been Fontana's intent when she wrote VULCAN'S GLORY. There are a lot more alien crew members, including several more Vulcans, in that book than we ever saw in "The Cage."