"Or " else....

There are over 400 words in the English language ending with the letters "or."  All that I can think of commonly  have that last syllable pronounced with the schwa sound, no long "o"--------   administrator, doctor, educator, janitor, mayor, impostor, litigator, legislator, coordinator, aggressor, counselor, instructor, inferior, creditor, juror, junior----and these are just some of the words referring to persons.  Others are factor, manor, glamor--the list goes on and on.  Why then are we constantly subjected to hearing the word "mentor" pronounced to rhyme with gore?  Kind of  a faux-sophistication, do you think?