Of course it can be, especially when he goes through a patch of shit form.
But, from my point of view, it's equally frustrating to watch some of the more aesthetically pleasing players not have any killer instinct in the box whatsoever.
For as much as Raheem's touch might often let him down, his positional sense is on a whole other level to any of our other attackers. Gabby, as much as I love him, drives me fucking mad every time he pulls back onto the penalty spot when a cross is about to come in. Grealish has a pretty shitty scoring record and I don't see any reason to believe he will ever get to Sterling levels. Foden's finishing seems to have dropped a few levels but I'd expect his composure to return. Mahrez might actually be out second best player at making late runs into goalscoring positions.
But it's also doing Sterling a bit of an injustice to focus solely on his movement. Lately he's been taking on his man successfully and somehow developed a left foot, which previously was absolutely shocking and suited to nothing other than standing on. Again, without wanting to focus too much on our summer signing, I genuinely think if Grealish had put together a string of performances like Raheem has just done then we'd never hear the end of it because some of Sterling's biggest critics are diehard Grealish fanboys.
Like I said, I'm not trying to be negative about Jack and I'm sure he'll come good or at least improve aspects of his game but the way both players are perceived makes for a pretty stark contrast and I think the reason for that is the way they look on the ball rather than the actual influence they have over games.