They don't seem either 'out of control' as he keeps saying or 'attacking [him] now' - as far as I can tell they're just segregating people into smaller groups on different sides of streets etc. so that they're more manageable for the comparatively small number of police.

It doesn't seem even to be about getting cameras away (which I would think wouldn't be surprising anyway) as he says towards the end - they actually seem quite unphased by that, other than keeping them a few feet away when they're questioning someone (it seems?) in the middle.

Just seems like a thrill or limelight seeking YouTuber not finding much of it, to be honest.

I have no such experience, but from the person talking it seems they are trying to get all the cameras out of an area so they can beat the crap out of those inside without being filmed.

It's classic authoritarian state intimidation tactics that they don't want recorded.