Interpretation a) they are not real. They are part of the game/simulation and are not real, therefore they can't log out.

Interpretation b) they don't have the correct command. Sometimes computer are very nitpicky on what they understand and how you have to formulate a command. But one person seems to say exactly the same as the one who logged out, so either the computer is very nitpicky on the specific timing of words, or the command is user specific.

Interpretation c) they are not allowed to do that. Like in they don't have permission to execute the logout command, like you don't have permission to shutdown the computer infopoint in a mall. Or think of it like the matrix, where someone doesn't want to let you out.

Interpretation d) subconsciously they don't want to. Imagine the command is not what you say but what you really want, so they can't log out, because subconsciously they do not want to.

Personally I tend to interpretation a) because there is this theory that in an endless or nearly universe, it is basically given, that some species will invent a computer that is capable of simulating an universe, which in turn will have a simulation going, because the same rules apply. Now if you follow this train of thought, you will arrive at the conclusion that for every universe, if there are multiple, there is a basically endless number is simulated ones, which makes the chances that you are not part of a simulation practically zero. Yeah, so that's that.