Probably because the two latest major versions - Ventura (13.x) and Sonoma (14.x) are not included in that list, and may not be supported. Patches to older versions may be supported. Apples patch policy according to Wikipedia:
```
Only the latest major release of macOS (currently macOS Sonoma) receives patches for all known security vulnerabilities.
The previous two releases receive some security updates, but not for all vulnerabilities known to Apple.
In 2021, Apple fixed a critical privilege escalation vulnerability in macOS Big Sur, but a fix remained unavailable for the previous release, macOS Catalina, for 234 days, until Apple was informed that the vulnerability was being used to infect the computers of people who visited Hong Kong pro-democracy websites.
```
``` Only the latest major release of macOS (currently macOS Sonoma) receives patches for all known security vulnerabilities.
The previous two releases receive some security updates, but not for all vulnerabilities known to Apple.
In 2021, Apple fixed a critical privilege escalation vulnerability in macOS Big Sur, but a fix remained unavailable for the previous release, macOS Catalina, for 234 days, until Apple was informed that the vulnerability was being used to infect the computers of people who visited Hong Kong pro-democracy websites. ```