Well, according to insane people who dribble a lot, they enforce orthodoxy.
You can see that in the hysterical pathetic antics of any Holocaust denier or creationist or flat-earther or 9/11 "Truther" ... they all froth and whine and bleat and moan about how peer-review imposes orthodoxy.
Meanwhile, in the real world, we can see how science has managed to develop and progress despite, or indeed because of, the existence of the peer-review process. And when I say "we" I mean those of us who are not paranoid lunatics.
Edited by Dr Adequate, : No reason given.