Bloomberg can literally spent 1 billion dollars during this primary...and still come out of the campaign with a larger net worth than before. The Bernie campaign can't do that.
More importantly, that terrible video is currently being shared on Twitter, where nobody but committed partisans will see it, and since this thread has assured me that the entire Democratic Party, all the cable networks, and every non-Bernie supporting journalist in the world is working to stop him from getting Bernie the nomination, why would they publicize something that would hurt Bloomberg, and likely help Bernie? Now, if maybe you want to say there isn't a giant conspiracy, then maybe that video may get some airtime, if the moderators don't want to ask about M4A for the 295th time.