Are such reviews always "pure opinion"? Things like "low salary", "bad manager" etc are always opinions no matter what but what if I am lying and saying "we do

Are such reviews always "pure opinion"? Things like "low salary", "bad manager" etc are always opinions no matter what but what if I am lying and saying "we do overtime every other month" or "it is acceptable and encouraged for people to slap interns"? Why to do in such case?