This is hands-down my favorite horror film in the last decade. It has so far been the only one since The Grudge to so unnerve me and even though I'm 28, I have made it a point to watch every mainstream horror movie I can- it's my favorite genre. The reason for my love is exactly what is said in the video, no really, every single reason given is why I love this movie. It doesn't rely on gore, it doesn't rely on jump scares (there ARE a couple, but not to the extent reviewers said there were- there's like, 3 of them in the whole movie) and it does something I wish more media would do in horror: involve kids in either peril or as the murderers.
I get why this movie doesn't work for a wide range of audiences: it's legitimately disturbing, again without going to the grotesque shock extent A Serbian Film and Martyrs did (both of which I like for just how hilariously, absurdly violent they are) and it DOES NOT end on any semblance of a happy note, it ends on a crushing bleak payoff that basically was all foretold from the beginning like the video said. I also understand that for many modern audiences out there, the lack of jump scares and dumbass characters literally written to die in as gory a way as possible might not be something they're accustomed to/condition by the film industry for. Every death in Sinister has already happened and they're not some idiot trying to get laid or get high, they're families, with a house and a dog, loving families all murdered together with no retribution and no hope for justice, again, something that modern audiences aren't accustomed to seeing horror movies.
There is a reason Cabin in the Woods (and Until Dawn) exist and that is that there is still a sad surface of camp left that resides on the horror genre by its B-movie roots and also that even still, the "best" horror movies today, as in best by the internet and reviewer standards, are teenagers trying to get laid, getting laid or just being teenagers. It Follows is a recent example of this- a movie that is an allegory for losing your virginity, a staple of horror movies, no original idea beside the succubus/incubus demon that stands in as a walking, brute personification of STDs. Again, think of Halloween, Scream, Nightmare on Elm Street, Friday the 13th, it's an extremely old trope and by now it's a trope horror should have shaken and evolved into dealing with stories such as Sinister, the fear of the unknown and the fear of losing your children, the fear of night and the fear that you can't protect your family.
Oh and the soundtrack for Sinister, mai gawd! It makes me weak in the knees with how great of a horror soundtrack it is. It is the sound of disturbing chants, it is a sound meant to bother you on a spiritual level (even if you're not spiritual at all) and make you think you're now hexed by hellish ghouls. The movie wouldn't have left such a effect on me as it did without the amazing soundtrack that it has.
Seriously, if you haven't seen Sinister, please go watch it. I understand it might not be your bag but it might surprise you! It surprised me when I watched a double feature of it and It Follows two months ago. Guess which one I love more...