> me being me, didn't have the courage to speak up

I hardly imagine a situation where speaking up is less "couraging" than using such tool to mock annoying person.

I think the word you're looking for is courageous.

Speaking up would have a higher failure rate. Speaking up overtly stimulates the annoying person's defensiveness and propensity to challenge back. Subtle manipulation always works better.

I imagine they keep their headphones on or play it off as the device doing it on it's own. The "work" of having to solve the problem hasn't gone away, but it has been translated from social into lying by omission and performative contradiction.

EDIT: By performative contradiction I mean doing the thing the person is doing to demonstrate the contradiction.