They suggest not using Tor Via Tor because someday they are going to make it impossible, but if they don't add layered entry guards for hidden services at the same point in time they will essentially be fucking hidden services. Hidden services can be traced up to their entry guards in a matter of minutes, the only reason the feds don't know the IP address of SR is due to an insane amount of incompetence, if it has any entry guards in the USA it wouldn't even require a warrant to deanonymize it past entry guards (ie: trace the hidden service) with a trap and trace / pen register. Using layered guards makes this attack more difficult, using Tor via Tor essentially is a work around to get layered guard nodes for hidden services, so I do hope that they add layered guards when they remove the ability to do Tor via Tor.