The response is very clear. Anoyhet user is tunning a process which blocks unelevated shutdown. You can override it with the command privided in the response. Like mentioned in a peer comment, sudo shutdown now would resuly in the immediate shutdown of the system, ignoring any interrupts. If anything else fails, interrupt power. It should start fine.

It could be a process you are running under a different user (safe), which demands you to shut it down cleanly.

Linux provides the mechanics to prevent the problem you’re angry about.

I don’t know why it’s inhibiting you here, but Linux is a multi-user OS (meaning multiple users can be logged in at the same time), so it definitely makes sense for it to have a mechanism like that. If another user is in the middle of a long-running operation, it might be very bad to forcibly cancel that…

Pretty sure using sudo or being root helps with that. Other than that: never have I ever seen that. Pretty sure this is a shit distribution.