Hello Markos,
If you make it a passive interface then yes, the interface can still receive RIP updates. I removed the sentence about the virtual router because this doesn’t really apply to RIP.
What I mean with a virtual router in this lesson is that someone could use something like GNS3 on their computer to run a virtual Cisco IOS router, configure RIP and send updates towards R1. This is a security risk.
Passive interface for RIP however doesn’t protect against this since RIP will still happily accept updates, even if the interface is passive (it only doesn’t send RIP updates).
With OSPF or EIGRP, it does help since a passive interface doesn’t send hello packets anymore so neighbor adjacencies can’t be established.
Rene