Yeah, wait until one of those camera people get assaulted by someone who doesn't want to be on camera. Then other media members can talk about media members getting their asses kicked. The cops can use that footage to arrest people and you get more content for your thread. Navel gazing! Everyone wins.
In this hypothetical, the cops wouldn't be arresting anyone unless either 1) it happened dead smack in front of cops, maybe even snowballing into cops and thus no footage would be needed, or 2) the aggrieved victims proactively delivered their footage to the cops and demanded action taken. There'd be no request for a subpoena, let alone granting of a subpoena for such footage.
And yeah, I'm sure whatever principles are being stood by re: footage would be upended when those media types have an interest in seeing justice for themselves.
You should look at that 21-page subpoena and see how narrow the fact pattern really is. It's not really 21 whole pages of reading; there's a lot of pictures that take up a bunch of space that show the Judge what the deficiencies are in the info they already have and what's needed to potentially assist with solving the crimes of arson and stealing guns*.
*and it's gotta be embarrassing for the cops to have to be solving this crime so publicly now, as the cops whose guns were stolen were/are getting investigated for why they left their guns in their cars to be stolen