Sprague I honestly don’t think you can fault me for not presenting all the info in front of you. This is easily accessible. You can read about it on the normal wiki page about Starlink under the section about space debris. Is that not an obvious place to look?
Starlink is a satellite internet constellation being constructed by SpaceX   providing satellite Internet…
The satellites are the payload. Yes, there is obviously a stage that brings the payload into the right orbit.
Since this is a low altitude one would have to actively maintain altitude to avoid eventual de-orbit. The second stage delivering the payload will naturally be in this same orbit which it would not be able to maintain for extended periods.
But you could just have looked up what happens to the Falcon 9 second stage. It is not hard to lookup either. They use fuel to have a controlled de-orbit immediately after delivery. https://space.stackexchange.com/questions/7814/what-happens-to-the-falcon-9-second-stage-after-payload-separation
I don’t think it is unfair to expect somebody coming with claims like yours does a tiny bit of research first.