That is pure rubbish.  A politician could be attractive, intelligent, experienced and have all the right answers to the important issues of the day, but if he was found to be a member of the Ku Klux Klan most people would view that as a litmus test.  If a judge was nominated to the Supreme Court and it was discovered that he had written a law review article saying women should not be allowed to vote, that would be a litmus test.  If a politician said that the terrorists who flew airplanes into the World Trade Center had legitimate reasons for doing so, that too would be a litmus test. 

In fact, there are many legitimate and positive reasons for litmus tests, and people who claim they don’t have any are either lying or they lack a well-developed belief system.  In either case, such people should never be entrusted with positions of power or influence.