I cannot say that I understood Dogtooth. That is not to say that I didn't appreciate it. What makes me appreciate it is its original idea, creative cinematography, and muted and detached mood. It was pleasant to watch (most of it) from a purely visual perspective.
But the content...
What can one say about the content?
It was difficult for me to settle into the film in some ways because it required for me such a huge suspension of disbelief.
I tried hard to think about what might motivate parents to raise their children in such a way. The father talked about protecting his children, but there was nothing rational about the way he went about it. Unless the mother and father were conducting some kind of top secret government experiment, or they were aliens or from the future, or some such. But that requires adding a layer that is never alluded to in the film.
I couldn't help but remember references to homeschooling in some of the conversations about the film when it was a Hot Topic. This doesn't connect in any way to my experience with even the most conservative homeschoolers. I may not agree with their methods or even their underlying assumptions, but at least its all held together by a worldview that has a measure of internal logic. The film didn't seem to have any of that.
So when the violence and the incest happens, it doesn't impact on more than a visual or surface level because it's not held together by anything. I didn't even find myself disturbed by it (well, the dead cat, yes) because it just all seemed so unbelievable. To clarify, emotionally vs. intellectually disturbed.
This includes the apparent inability of the "children" to recognize that things are amiss. Granted, the oldest does eventually, but the other two seem unaware that what's going on is everything but normal. Again, it's pushed to an extreme that makes it unbelievable.
There were interesting elements, no doubt. The brother over the fence, the monotone manner of speaking, the airplane business. But it didn't convince me.
Now maybe I'll go back and re-read the debate from earlier this year.