Seems to me that the problem is, well, precisely as stated: overthinking. It's the same problem as with close reading: look too close at a sample of one and you'll start getting noise, things the author didn't intend and were ultimately caused by, oh, what he had for breakfast on a Tuesday ten months ago and not some ominous plan.
On the other hand, where do you draw the line between reasonable analysis and overthinking? I mean, you can read into a text things which only your own biases put there in the first place, but on the other hand, the director of Birth of a Nation allegedly didn't intend to produce a racist film. I've argued plenty of times myself that you can clearly go too far, and critics often do, but on the other hand, while the creator determines everything that goes into their work, their intent, as far as they can describe it, is just the rider on the elephant, and the elephant leaves tracks where it pleases.
Another month has passed and here is a new rationality quotes thread. The usual rules are: