I have a very similar USB crossflow fan, it has a noisy motor to. I call it a mini air conditioner since the loud brushes make it sound like a AC compressor.
I agree, a different motor probably would have made it tolerable. This was not exactly inexpensive, there seemed to be plenty of money involved for a better motor to be utilized.
i got a usb tower fan from ross and the barrings were non existent and just loud, didnt blow any air the moter got really hot and melted. it was HORRIBLE IT WAS ALSO VERY VERY VERY LOUD and it was ment to be use in offices and good for sleeping is what was advertise