Actually it doesn't. I recently uploaded a testvideo over flare.pub, which uses NIP-71, and I don't see it there. (I am already following my own account.)
Discussion
... I mean, I don't see it in that third tab in Amethyst.
It's because flare is not including the mime type of the video. So amethyst doesn't even download (we only download the videos we support and can play)
But when I link to the video event, it works even in Amethyst.
Yep, the content type filter is just for the middle feed. Otherwise, there is a lot of junk that gets downloaded that the app can't display.