Can you completely disable/ignore content shared by other users if you're playing against them online?
Yes, nothing shows up during actual gameplay.
You misinterpreted the question. If I don't want any video of my gameplay shared, but I'm playing against some kid who records and shares his uber-mad-leet skillz all the time, does his game not record the gameplay featuring me because of my preferences? I believe I'm SOL in that case and the footage of me gets shared against my wishes.