(The concept of 'superior' and 'inferior' races are, logically, meaningless. It's emotional and illogical to believe in such things. Solok, being Vulcan, is not entitled to that.)
I don't understand this sort of PC bullshit. If species A has greater strength on the average than species B, then species A is superior in strength. If A has better memory than B, A is superior in memory. And so forth.
It can be debated till bovine rehabilitation whether a good score in, say, hearing will restore the worth of species B after it has scored dismally against A in everything else. But Solok need not be concerned with that. He can count the score of Vulcans on those points that pertain to prowess in Starfleet service and compare it against the score of humans, and reach the absolutely correct conclusion that Vulcans are superior to humans as Starfleet officers and crewmen.
That is, assuming that the scores justify that. But we are given no reason to think they would not.
Certainly Solok comes off as a bigot because the impression we get is that he believes in "overall" superiority of Vulcans, whereas as already said, that's a battleground without rules: anybody can come and say either that
a) all species are equal because the various easily observed superiorities somehow always happen to cancel each other out exactly or
b) in fact B is superior to A because the one attribute where B triumphs is more important than all the ones where A triumphs put together.
Of course, a) and b) represent true
bigotry, a deliberate perverting of facts by the introduction of frivolous "weights" for the scores, but Solok's position is weakened if he tries to extend his argument outside a certain set of parameters. Then again, his audience is likely to consist of bigots who won't bother to listen even if Solok defines his parameters.