It seems like you're misunderstanding what parent meant by "prerecorded" - not a screen recording, just pre-writing of commands to be executed during the demo. Would you consider it "deception" to hit up arrow a few times in a terminal during your demo to execute a command from shell history? This is effectively the same. Take a look at the linked repo, it's very clever.
The original link for itsalive says it works by making it not live and the op says just as much.
This is very different from practicing a script and you actually doing all the actions in real time. You're allowed to rehearse for your live performance but unless you're doing it live then it's not live.
People also hate lip syncing because it's a deception of being live.
And yet, ~all singers lipsync, because the point isn't to show off what the artist can do vocally every single night, but to entertain the audience, which lip syncing achieves.
Are you assuming or do you have evidence to back up that claim. Because I actually go outside and watch musicians perform. Are you telling me they fake the errors too? LOL
