I'm not 100% sure, but I think this tool just types the commands. So it avoids typos and you can just focus on what you're saying as you type nonsense. Sounds like it actually does run your pre-written commands. From the readme:
> What's more, It's a Live is actually running the commands you're typing, so you have full interoperability with other
programs.
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.
