Earlier quoted context omitted.
Yes: End-to-end encryption is technically quite difficult, but politically and legally feasible (at least currently, at least in most countries). Simply not cooperating with law enforcement is technically moderately difficult, but politically and legally impossible. Between a difficult and an impossible option, the rational decision is to pick the difficult one.
Is there a nice solution for multiparty (n >= 3) end-to-end encryption?
A possible implementation using existing infrastructure where at least the client is open: modify the messaging client so that when it receives multiple pvt connections it routes every incoming message to all connected members. Now if you have say 10 users that want group encrypted chats, have one of them run the modded client too so that any user connecting to a pvt chat with that client will essentially enter a room with other users. Of course this requires trust between members, and adding another encryption layer on all clients might turn out necessary so that you don't need to worry about the carrier telling the truth (all p2p connections encrypted, etc)..