I use RVparkreviews regularly. I find the totally negative reviews to be the ones I question the most. If I see that the reviewer has posted several negative reviews I am inclined to ignore anything posted by them.
We have stayed at parks with significant negatives because they were convenient for some other reason - generally location. Usually the negatives are present - railroad tracks are not likely to move nor are highways, small sites will still be small. Knowing in advance is helpful but will not drive us away. Rude staff may or may not be an issue by the time we arrive. Awful refund rules, usually posted someplace, will prevent us from paying for more than one night at a time!