I'd imagine that all depends on the criticism being leveled. There are plenty of things to criticize about Jerry Jones. And then there are plenty of ridiculously unfair criticisms, too. I can't speak to whatever other boards you frequent, but I can say that from what I've seen, the reaction to Jerry's handling of the front office by Cowboys fans is pretty uniform everywhere. Yet there seems to be this belief on CZ that people defend him, where that's often just not the case in the actual threads.
We're looking from the perspective of being a quitter in 2010, followed by a trifecta of 8-8 finishes. We're also in the midst of an offseason where the team basically doubled-back on it's widely-applauded cap stance from just 2-3 years ago, reaffirming how poorly they've handled things in the past. Having those results at hand, it's pretty easy to assume that not many are currently happy. Furthermore it would be incredibly hard to make a convincing argument for the guy for someone who was happy.
People may not be supporting him now (which should be anticipated given the results), but that wasn't always the case. In fact, there were times in the recent past where people have applauded Jerry's front office moves.
Ciskowski received a lot of love 5-6 years ago when he stepped up after Ireland left. Almost positive that there was a big push behind the idea that Tom was more instrumental than Ireland as a means of justifying the loss of Ireland at the time. When people first suspected Stephen assumed a bigger role, it was met with great applause from a large portion of the board (myself included). And most recently we have Will McClay being a very hot topic even though he's been with the team for years. Overwhelmingly these were well received moves at the time so it's not as if posters who supported Jerry's moves just never existed. I myself was pretty excited with the Stephen aspect at the time and I'd wager that a good number of other posters were just as excited with the Stephen aspect.
Although it may seem that there isn't support for Jerry, it wasn't that long ago that people were jacked about the Ciskowski and Stephen moves. Certainly wouldn't be classified as a long, long time. I will agree that pro-Jerry posting is likely at an all time low, but it certainly hasn't been that way for all that long.
As for public opinion, I don't believe the opinion is all that uniform. Guess that's why some fans look at some of the recent activities as "signs of change" whereas others view it simply as a product of circumstance. There was a thread a while back about the evolution of Jerry because Jerry was cutting players he wouldn't have a few years ago. You can pretty much take it to the bank that something similar was brought up when Jerry cut TO. There have been countless "Jerry Basher" vs. "Jerry Apologist" threads arguing both legitimate and fabricated criticisms. There have been a number of discussions about the Cowboys' front office structure compared to the rest of the league in order to try and paint Dallas as being just like everyone else. Then we have the
"I thought only Jerry Jones......" or
"Imagine if Jerry Jones......" type threads.