It's a completely different backend. u/d3rr was apparently unaware that the backend for admin tools was included, so he rolled his own quick one. But if you need someone shadowbanned, use the console to set their _spam flag. Since they're separate functions a message would not be sent for shadowbans, but would for normal bans (or suspensions, if you want to switch to that). Iirc you have to program the system account to send a PM automatically when a ban or suspension is fired.

I do think suspensions might work as a replacement for users who became unbannable after the 500 error happened when attempting to global ban them, which seems to be getting more common.

If I have time I can make some changes myself and test them, assuming the github is up to date. I could add a frontend for shadowbans and suspensions. I'm guessing the reddit admins have a completely separate program from reddit that they use to take these actions.