I tend to agree with you. They have been going up against publicly unpopular targets, so few have questioned them thus far, but there's no reason that can't be a ruse.
Part of the problem here is the fact that they really are anonymous, so if Anonymous goes after two different targets on two different days, there's no way to know that it's actually the same group both times. So even if you could prove beyond a shadow of a doubt what their goals were for one particular attack, that would have zero bearing on the motivations and goals behind any subsequent attack.
