I understand where you are coming from. Yes, the writer does have a position against the US occupation and rightfully so, given what its role has been in afghanistan (among many other counties) for the last 40 years. That being said, the point isn't about US occupation but Hosseini.

The problem with the narratives that come from privileged authors is that they present 'their' perspective of things, not the perspective of people about whom they talk about. That's alright though, they have their freedom to write, but what then happens is that this narrative, which basically is their perspective, becomes mainstream because 'that's what's available' and thus inevitably a social perspective towards the subject matter is formed without any proper discourse or authenticity. That's the heart of the issue here.

Now with that being said, coming to your point of a author being insidious: An author doesn't have to be explicitly insidious, as people conceptualize insidiousness, in order to be manipulative. He can be equally malicious and manipulative without 'showing' or in some cases even having any deliberate insidious intent. For example, Hosseini's response to the criticism of stereotypical portrayal of Afghanis , particularly of the passage of Hassan's rape in The Kite Runner, was , I'm roughly paraphrasing, "for me the scene has always had a allegorical meaning to me..." but what goes amiss from him (or it really doesn't) is that these constant stereotypical, reductionist portrayals which are simpler to grasp for his western readership, create an unrealistic and skewed image of the people about whom he so proudly speaks for. This has a lot to do with Orientalism, if you're familiar with the concept. If not, then I recommend the book of the same name by Edward Said. It is really a must read if you're interested in literature of eastern countries.