It's not ridiculous. Those conditions have defined restrictions that are less than what would be "realistically" assumed for the sake of game balance.
Also, it's heroic fantasy. The martial guy being able to AoO even while stunned is badass and cool and should be allowed anyway.
AoOs are not actions, but they are attacks and they still require you to be able to move. Anything that keeps you from attacking, such as Nauseated, prevents AoOs. Anything that prevents physically moving at all, like paralysis, prevents AoOs.
Effects that merely take away your actions do not prevent them.