Because it points back to a decision from the WH, one of which Petraeus provided cover??
Petraeus is an angle I haven't heard before. Trails leading back to the WH is though.
There were four versions of Nakoula's movie.
Only the final one was forwarded, by persons unknown, to Sheikh Khalid Abdullah the cleric in Cairo who aired it on TV. Nakoula, the maker of the original film, was not the one who uploaded the final version, Innocence of Muslims, to the internet.
You can hear some interesting things about the timeline of all these iterations of "the movie" in the Youtube video linked below. Start at 9:30 and watch to 16:00 for the meat of that. The trail leads to a defense contractor.