Maybe not as much as an oversight but (as I understood) mostly due the fact that most ccTLD registries predate the existence of ICANN. As the ccTLDs as such weren't issued by ICANN, there's no ICANN policy that would apply to them for stuff like this.
Countries view ccTLDs as their sovereign property and territory on the Internet, and refuse to be (involuntarily) bound to any rules or requirements as a matter of sovereignty. It’s a huge source of geopolitical conflict within the IANA/ICANN split (and with DNS in general).
A number of countries have _voluntarily_ agreed to follow ICANN’s principles for good management and interoperability [1], but jurisdictions gonna jurisdict I guess.
