Because Anderson had one fluke season and relatively speaking Anderson isn't that good to begin with. Just because he hasn't improved doesn't mean he isn't working hard.
He didn't have a fluke season, he had the same type of year that Rex Grossman had the year prior. He came on the scene making big deep ball plays and light up the scoreboard... Just like Rex the second half Derek Anderson sucked, just nationally it wasn't scrutinized because he at least still had 2 high end receiving weapons. Teams figured out DA's weakness quickly that he couldn't throw an accurate short pass to win a game.
This according to some Cardinal's fans is a trend to see DA laughing on the sideline, so the reporter had his good mind to ask it, especially if it's what the fans want to know about the ongoing thing.
Is it dumb yes, but it's relatively no different than the Chicago media constantly wondering about Jay Cutler's sideline gestures and body language. Just if a reported has asked Jay about it he isn't foolish and gonna flip out like DA.
BTW: Rex Grossman busted his ass too, they just aren't starting QB material because they aren't complete quarterbacks. They are both extremely flawed.