Again, these tests have NOTHING to do with *ability*, and everything to do with cultural/institutional fit of a candidate into an organization.
Are they perfect? No, absolutely not, nothing is...but they are another tool in the HR arsenal to mitigate the risks of a candidate ending up a liability to a company as an employee.
And for the record, I think the tests are bunk too and miss a lot of good people..but legally discriminatory, absolutely not.
I never took MMPI, but Hogan was little more than the same question asked four-six times with varying degrees of 'intensity', with at least one absolute trap question for integrity thrown in, ie. "I have never lied" - True or False. EVERYBODY has lied in some fashion, so if you answer True to that you're done. Then you get "I try not to lie", "I lie to others often", and "I sometimes tell a little white lie to spare someone's feelings". Doesn't take a Tier One Rocket Surgeon to figure out where the goalposts are there...