The fact that Tor is mentioned would suggest that you have to add that to be secure.
For users in extreme circumstances, Tor gets them a lot, but it also adds a lot of overhead; you'd want to avoid it if you don't need it, not just for your own sake but also for the sake of Tor's finite bandwidth. There is a lot to be said for having a feature like Tor be supported-but-optional, opt-in, and interoperable with users who are not on Tor.
I did consider the idea of allowing Tor hidden service addresses as an alternative identifier to IPs, though that idea comes with its own compromises: you'd only be able to talk to other Tor peers, for instance, or, alternately, every peer would have to be on Tor.
The latter case is obviously a non-option. The former case would kind of work, but the Tor-hidden-service peers' effective network size would be much smaller (since they can only talk to Tor peers) and thus easier to compromise. This is obviously bad - users in need of greater security would end up in a less secure version of the network - and if this subsection gets owned, that could have a second-order impact on the network's overall resilience.