That's what I mean: you can't close it. It automatically re-opens. And when you navigate away from it, the sound continues. I finally had to mute my whole system to get away from it. :-x
So, later, when I find a video I want to watch, I'll probably have forgotten that the sound is off and will think something's wrong with the desirable video.
To me, a video that can't be turned off rates as spam.