I can write a scathing review for any one of my favorite movies. I even thought the other day it would be fun to do just as an exercise. You can see the good and bad in everything, it's just a matter of which perspective you take. Yes, White backs it up. That's why he gets more attention than some random blogger who writes "This sucks, zero stars". There comes a point, however, when someone is seeing only the bad in things that are widely liked and only the good in things that are widely disliked, that you have to wonder if that person is simply being a contrarian just to get the attention. You start to question if "his opinion" is his honest reaction, or would be his honest reaction if he didn't approach movies with an eye towards being contrarian.
On the other hand, if White is genuinely getting people to examine their feelings about what makes a movie "good" or "bad", then he's a positive force. I kind of doubt that's his intention, but if that's happening, then more power to him.