If they want to use a giggle switch and they're irresponsible with it and someone gets hurt, that sucks, but it doesn't have much to do with the threat of white supremacist terrorism that the other person was talking about.
If you're irresponsible and you're shooting without knowing your target and what's beyond it, you're already in breach of a law called reckless endangerment. You might be able to do a bit more damage that way, but ultimately you can empty a 30 rounder or even 3x10 rounders pretty fast with semi-automatic too. Adding another law on top to restrict the type of weapon doesn't really make anyone much safer.
Plus if you're really that concerned, just look up the Yankee Boogle. It is a tiny, easily 3d printable piece of plastic that you can drop into the action of an AR15 and make it full auto illegally in seconds. Run into cops? Chuck it in the bushes and make another tomorrow.
Resticted mag sizes? Mags aren't that hard to make out of sheet metal from a hardware store, and changing mags doesn't take that long. None of this stuff really makes people much safer if they're left inside with the shooter for hours whilst the cops cower behind their cars and stop parents from trying to save their kids.
Trying to make people unaware of this doesn't actually make anyone safer. You can cry about the rights of a multinational corporation to control speech on a platform that should be a public commons, it doesn't change what is effective, and we've all learned from decades of internet history at this point that trying to stamp stuff like this out just doesn't work. It's always going to be there.
Also, youtube isn't going to maintain its monopoly forever. It's enshittifying and peertube is waiting in the wings to pick up the slack. Then it really won't be up to youtube anymore.