I don't get the need to have strict definitions for horror, but whatever.
The fact that texas chainsaw (
)is even in that list automatically gets the
treatment. For the sake of that argument, lets just say (and I'm parsing words) that I disagree with the notion that a film based on "true events" can't be horror. It's not a documentary. The reason why they're so effective at being horror movies, is due to reality affecting people (way more than most) and there are facts for people to connect with. It's the reason why people were scared to go in the water, scared to take showers, and scared to be at home by themselves, back in the day. A shark actually exists in the ocean. The Chainsaw shyt actually happened. The minute you add shyt like The Girl Next Door and The Snowtown Murders, and that train of thought gets derailed in a crazy fashion. Hell, half of the goat horror films were inspired by actual
events and people and the movies end up being a lot more tame in comparison.
The Bergman film was paced, lit, and payed off like any other horror film (even with it's theater like aesthetic/feel). The only reason it might not seem like it, is due to the eyes one sees it with it today. It's old and came out in a different period of time, but it's still exploitative and still highlights the real violence against women that was later used as shock, a form of empowerment, and to disgust audiences.
At the end of the day, I think it just becomes an exercise in shouting opinions about what one feels to be horror. There is no "right" answer, especially when you have genre blends when the director actually did a perfect job of blending the themes together. Word to Terminator 1 being a slasher, with an unstoppable killing machine, whom only died due to pure circumstance... the same way Jason and co go out.