Basically that refs are going to make mistakes, Given the overly complex (in my opinion) nature of many of the rules will cause them to make even more mistakes. But these mistakes will even out. If I went only by what I read week in and week out in threads such as these you would think only the Bills get bad calls.
But yeah you are right, by the thread title you can generally tell which ones are the ref whine fest ones and skipping over them is probably the smart thing to do.