DS loves TV (probably because we hardly ever let him watch), but for several years was very scared of any kind of alarm because he was anticipating that it might go off. For a few months after we got a carbon monoxide alarm, he would ask repeatedly about how it worked, and what would make it go off. And I just remembered that he was also very scared of the washing machine. Mostly it's quiet, but will make sudden noises.
If your son is very sensitive to noise, it could be that he's concerned about sudden loud noises from the TV. Commercials were shown to be significantly louder than the preceding TV show - to someone who is sensitive I could see how it would be jarring. Maybe you can change the audio settings - many TVs have an audio mode that limits the range of decibels.
With regard to the pop culture issue - my opinion is that there's actually more danger in a kid becoming TOO obsessed with the latest thing, so, if your son doesn't seem to mind not knowing what's cool, then maybe it's a good thing! Leaves him to explore his own interests rather than chase after those of the crowd.
