Most employers do now. Many have as part of their application process a background check that does a deep dive in all social and online presence.
Background checks are not about parking tickets and DUI arrests anymore.
A criminal background check I can understand.
Not allowing someone in college because you are deranged Leftist lunatic and want discriminate against Trump supporters?
Really you think that is acceptable?
The employee doing the “what is your political stance” check should be fired.