The guy that reviewed it on IGN must not have seen The Gallows, Devil's Due, The Devil Inside or Paranormal Activity 4, all of which are about as close to a one star review as I'd go.
Yeah, Sinister 2 isn't good, but it's not a 1/10. I mean, I'm all for differing opinions and I'll agree that for the most part it's a pretty worthless follow-up to the promising premise from the first. But it is by no means unbearable to sit through. It is the quickest ninety minutes I've ever spent in a theater.