The administrative logic couldn’t be simpler – If the servers are in Russian territory, they’re under direct regulatory control of the Russian government. You may not be able to plug all the holes, but if you can plug most of them, you’ve got less operational stress on your security.
Of course, there’s a lot more to this approach. Disconnecting doesn’t mean there aren’t external connections and operators who can continue their adorable hobbies outside Russia. Disguised operators using virtual private networks (VPNs) are also not necessarily affected at all. (That said, Russia could use the new national network to crack down on VPNs as China has been doing recently, too.)
Some predict economic disruption as a result of the disconnection, but there’s no indication that any hiccups during the…