Does anyone know what standards / processes are for de-peering, or as in this case, revoking ASN entirely, of rogue networks?

The notion of ignoring networks (ASNs) which have predominantly hostile traffic at the BGP level has been bandied about for a long time, but so far as I know, most network operators are exceedingly reluctant to do this, absent a few, mostly political, instances. Israel and its Arab neighbours come to mind, my understanding is that direct network connections are limited, or at least were historically. There are a few other cases largely between hostile nations.

Would RIPE be acting on the request of German legal authorities and/or courts, or on some other basis? And how would this be determined?

small hosting operators usually have few actual paid IP transit upstreams (2 or 3 max), which can credibly disconnect them based on criminal activity.

they also usually have a small number of actual manually-configured peers and if they're a member of an IX, they use the routeservers instead. Very easy for an IX to disconnect a criminal entity.

disconnecting a HUGE network that has a large portion of abusive traffic is much harder, like trying to bgp blackhole some major ISPs in China.

For small ASNs wanting new connections it's getting pretty common for peers to require a RPKI/ROA (a cryptographic verification system used to automatically configure what advertisements are accepted based on what resources your RIR says you have and what you crypto sign on how you want to advertise them) instead of a LOA (letter of authorization, a document they can put on file saying what you intend to advertise). With this your RIR becomes the trust anchor (and signer, if you don't want to deal with delegation) so a revocation of the resources by the RIR should automatically result in your advertisements being rejected by your peering points in most cases like this going forward.

This is getting uptake because instead of the pitch to operators being "help validate internet advertisements" it's "now you don't have to manually configure accept policies or worry about misconfigured advertisements from clients".

https://www.arin.net/resources/manage/rpki/troubleshooting/#...

> Would RIPE be acting on the request of German legal authorities and/or courts, or on some other basis? And how would this be determined?

This is a guess but either a) giving out incorrect information (which is a clear basis, all AS operators must be either a person or a legal company, yes you could practically bypass this by registering a shell company but considering that they've used PayPal I'm pretty sure that they have not planned this well) or b) a German or Hessian (it seems that it's registered in Hesse) court might have forcibly transferred the legal entity to the state, in which case since the state now owns the entity they could simply file paperwork to voluntarily relinquish the AS.

Depeering is much more easier: all major transit networks have a provision in their contract to terminate the transit if it's unnecessarily burdening their systems or if it is used for malicious purposes.