Why not?
One thing that Holland has stated (and so I think it's an organizational thing) is that you can't judge a player based on their first 10 NHL games or so (in a row). For those 10 games or so, a guy is running on adrenaline and can really provide some pop. However, the real test is after that, where the adrenaline has worn off and you can see how a player's skill and mental game match up. I know we point to Tatar's first 10 or so games as if to say "look at how much better he'd be ALL of the time," but it's possible that's not exactly accurate. It's hard to make a case that he didn't tail off a bit during those 9 or so scoreless games.
The other thing is, Tatar wasn't a worldbeater BEFORE his callup and he isn't one now after it. If he's a guy who truly belongs in the NHL, he has to play like it. Nobody earns an NHL job as an offensive player by playing (and scoring) like he has lately (2+2=4 and a -2 in 10 games in the month of April). In all, he had 5+6=11 and a -5 in 20 games since going back down. Those aren't the numbers of a guy who's done with the AHL. Hell, Jurco had 6+6=12 and a +4 across those same 20 games.
I know we say "oh, well, he's discouraged and it's affected his game" but he couldn't have known that he wouldn't have gotten another callup. That would have been a reason to play hard, not sweat the small stuff, and earn another one. It doesn't make much sense to say that he was discouraged and didn't try as hard. If it somehow does, though, it probably indicates a serious character flaw and he won't be long for this organization. What would be next, being 'discouraged' over a lack of icetime?
I think Tatar is going to be a good player, but I don't think the case for Tatar as fantastic NHL-level player right this moment is as self-evident as most of this forum thinks.