Considering the few dotted lines of the very short filter that came AFTER a bunch of parked cars AND the fact that the van spent most of its time in the middle of the striped area AND the fact that van had to cut in hard to enter the left-filter while avoiding the islands, one can deduce that:
1) the van was going too slow to have given biker a chance to move over (as van desired). Error, drivers do NOT see cyclist as speedy.
2) van wrongly expected bike to be going left, due to not indicating left OR right. Error.
3) van was going far too fast for this manoeuvre, making the whole thing look dangerous. The van did give space in rear-cam shot, but cut in hard.
4) driver was tired, hungover or just an obnoxious git. Or all.
Personally, due to being in similar situations, and once having a car try and edge me off the road deliberately (all because I got ahead at the lights ffs) I always indicate, even at a filter going ahead. I don't do this in a car because I have power & weight. At roundabouts I often indicate to the waiting cars that I am getting off, thus allowing them to relax and pull out.
I imagine that most car drivers are often a-holes & impatient, so if I give a good account of cyclists, on my way home, to just a few drivers they will be calmer further up the road to the next cyclist. Yes, i'm that nice
I point 45 degrees down to enter a filter, as opposed to a 90 degree for a hard turn.
One other thing I do, when i'm going slow & hit what is a blind corner for cars, is to actively wave them to overtake me. Some wave at me in their mirror, some honk. We will always meet the idiot in the video,sadly, but even though he was in the right (the cyclist that is) I'd personally have indicated my 45 degree thing. After all, you are not encased in metal, you are squidgy, and every driver is tired & hungover.