(used to be a college test prepper) Those “obscure words” are fair if they’re presented in context and the student has to ascertain their meaning from that. They’re fair in analogies if roots, prefixes and suffixes make it reasonable to figure out their meaning. But multiple choice lists for the meaning?....it does disadvantage students whose language skills did not originate in very erudite environments.
It “disadvantages” students who don’t know as much as others, which is the point of the test.