The maker of the hoax Bernie Sanders video has confessed. Matt Rettenmund has his statement at Boy Culture:

“So long story short, this was a social experiment, and everyone seem to fall for it. Im a Bernie supporter but one of the main things that I set to prove is the medias ability to rewrite headlines and make everything seem twisted. The video was a joke at first, I imagined a 70 year old man walking out to a song that has a hard intro (subtract the homophobic lyrics, which is why it isn’t in the video) but as i thought about it, i knew everyone would go nuts, i just want to give a major shout out to boy culture for keeping a level head about the situation. The video was faked, if you’re going to support a candidate dont do it cause of a viral video, and if it sparks you’re interest, let the flame burn a lot longer than just voting and walking away, we as american citizens have more power than we think, and to all those people thinking they got a 1up on Bernie….I say this…”

UPDATE: Acuna has sent a similar statement to Salon.