The nitter video could literally be a piece of iron, even a ferromagnetic object will turn like that under the presence of a magnet. It certainly isn't proof that the thing they have there is NOT a superconductor, but you can't use that video as evidence of anything.
Iron and ferromagnetic objects would not react that way. The key to this showing diamagnetism is the fact that the same points are repelled in the same way regardless of the orientation of the magnet. If it was ferromagnetic, you could have it stand up on it's tip in one polarity and stand up on another portion of the object in the other polarity, but you couldn't make it stand up on it's tip both times.
