[kube-system]

There are hundreds of TLDs that prohibit proxy registrations. .us is one of many.

e.g. https://www.domain.com/help/article/domain-management-tlds-n...

It is quite logical for TLDs with nexus requirements. Not every TLD operates like a free-for-all in the way some of the more popular gTLDs do.

[ssnepenthe]

Something I've been wondering about lately - maybe you have some insight into how this works?

The .in TLD doesn't allow privacy protection as seen in the list you linked above but whois still shows "Redacted for Privacy Purposes" for everything but the country and state/province of the registrant.

[kube-system]

I'm not sure about .in specifically, but it is worth noting that the information you are required to provide to register a domain and the information that is published on WHOIS is not necessarily the same.