It is not, but a write amplification of 36704:1 is one hell of an exploitable surface.
With that same Raspberry Pi and a single 1gbit connection you could also do 333333 post requests of 3 KB in a single second made on fake accounts with preferably a fake follower on a lot of fediverse instances. That would result in those fediverse servers theoretically requesting 333333 * 114MB = ~38Gigabyte/s. At least for as long as you can keep posting new posts for a few minutes and the servers hosting still have bandwidth. DDosing with a 'botnet' of fediverse servers/accounts made easy!
I'm actually surprised it hasn't been tried yet now that I think about it...
How is it nonsense?
The EU law is that the reject all should be exactly as easy as the accept all button. 1 extra click, however minor of an inconvenience it is, is extra effort. And therefore strictly speaking in violation of the law.
Nothing will ever happen but it's valid criticism.