Indeed the very first objection you got was "literacy tests are racist". If you read the wiki page for it you'll see that the argument is not about whether they actually tested literacy or not (after the initial phase when "good moral character" exemptions disappeared), but rather whether it was legitimate to exclude new waves of immigrants who didn't speak good English at all (Italians, Russians ...).
Whether to even check the ID of voters in a rigorous way is opposed on similar grounds. If you can't check the ID of voters you certainly can't check their ID when they apply to become bureaucrats, and if you can't even answer "who is this applicant" then how can you answer more sophisticated questions about them?