A documentary that is misleading, often using slight of hand and statistics, purposely designed to fox* you.
*Fox = To trick or fool by ingenuity or cunning; outwit. To baffle or confuse.
Note: It is often incorrectly thought that 'foxumentary' came about as a disparaging term for documentaries seen on the Fox network. This is not the case, and all networks my put out foxumentaries. It is merely a coincidence that the fox network is perceived by many as putting out nothing but foxumentaries.
"That anti-environmentalist film was a foxumentary."
One of those easily available and condescending cultural documentaries produced by self-serving anthropologists. They gratuitously display the naked tits of native girls that young boys can fap to without censorship.
"What are watching?"
"A fapumentary about a tribe in the Amazon rainforest. It's on PBS so they can show their titties."
"Sweet."