"Fan" is short for "fanatic" so expecting them to be reasonable as compared to a sober judge is useless. There are, however, more reasonable fans than others. Expectations based on reality is what separates them. I lived most of my life in Kentucky and the only time the basketball Wildcats lost a game was when the referees cheated us. At least that's my recollection. After I moved away from Big Blue Madness and saw how the same thing seemed to happen to other teams I figured out that it might be unreasonable to blame the refs for everything. Or the weather, or the injuries, or the luck. Some fans cling to that and God bless 'em as we say here in the South.
I don't see anything wrong with being critical of one's favorite team if you truly want to see them get better. And I don't see anything wrong with NOT showing up when you already know how the story is going to turn out. Those both seem reasonable to me. This goes for individual players too. Yes your favorite player has flaws. Some will fall short of Sports Glory but that is part of the game. Getting riled up about others taking note of it seems childish and not fun at all.
One thing that is good about both types of fans is when they set high standards and demand that they be met. This is not the same thing as expectations - every team will have a down year. But when fans just accept good enough for a program then that's what they're usually going to get. Making excuses won't feed the Georgia Bulldog for example. Now I'm not saying that fans who gripe non-stop will actually make the team play better but when the people behind the scenes feel enough pressure then improvements are made. It helps to have smart people of course.
Which brings us to the Falcons. Blank is going to give the Smitty/TD duo another chance. It is a risky move since it's not likely that the Falcons will make the playoffs for the next two years. Then Blank will have to decide again if these two can get it done. Some fans point to Smith's winning record and Dimitroff's two awards for executive of the year. True, these two have built a winning team. The question is - is it a Super Bowl winning team? The window closed last year on 4th and goal. They've got to start over now. I don't think the past is going to help them with Ws.