(If you look, most other toggles that appear under "Content & Privacy Restrictions" are for similar things: things Apple provides no more-visible setting to disable; because they think you have "no reason" to turn these features off; because these features are, at least in Apple's opinion, "unobtrusive" [i.e. only really doing something if explicitly activated] and "costless.")
In contrast, I presume the underlying setting identifier, as appears in `defaults` and/or MDM profiles, has a more sensible hierarchical prefix based on what potential risks an organization would see in a roll-out of LLM use.
ETA: yes: the macOS settings domain for "LLM stuff" is `com.apple.applicationaccess`, and the declarative-configuration namespace is `com.apple.configuration.intelligence.settings`. Neither of which has anything to do with parental controls per se (though `com.apple.applicationaccess` is generally where MDM settings related to preventing employees from using "potentially insecure" device capabilities live.)
There's also the declarative-configuration namespace of `com.apple.configuration.external-intelligence.settings` ...which is a bit of a bass-ackwards use of their own declarative configuration model, since if it had been `com.apple.configuration.intelligence.external.settings` instead, then the settings in the enclosing "intelligence" namespace would serve as fallback defaults for the external-intelligence specific settings. Ah well.