You'd have to run your Urbit node off a anonymous crypto-paid VPS to ensure a separation of Urbit identity and your government slave name.
I recognize it wasn't particularly clear, but the emphasis on 'an' IP address in my message was meant to convey that for the strata of users interested in the platform (and also maintaining perfect anonymity), obtaining regular use of an IP address that is not necessarily associated to them shouldn't be an issue.
This could be through anon VPS providers, rooting random routers, or any other means, but what it amounts to is that the people who would potentially benefit from the service won't care about the IP they're using being shared, either because they've taken steps to mitigate that risk or simply because they don't value opsec to that degree.
The only failure mode is people genuinely not being aware that their IP address will be linked to their Urbit identity, and these people are generally filtered out by the obtuse process of joining anyway.
re: running it through TOR, I think most if not all nodes just drop UDP packets instead of routing them, somebody would need to put a lot of work into hacking together a solution that doesn't compromise anonymity like most "UDP over TOR" solutions.
I think Urbit is neat and Moldbug is right about wh*te people. But Urbit has a lot of problems and that's not even a reference to it's "bunt a mold" rune programming language. At this moment in time it's a glorified chat program and it's not even particularly good for chat. I'd never shill a chat application that forces you to broadcast your IP by requirement, but that's exactly how Urbit works.
I find that when compared to the p2p competition (which is all hacked-together garbage that barely works) it's a breath of fresh air.
It is fairly useless at the moment though.
