How can you know it’s not the earring giving those testimonies? The story doesn’t say whether they were wearing the earring while being interviewed, but given that wearing it for a long time wastes away your neocortex and turns you into a flesh puppet, I don’t think long-term users are even able to speak on their own anymore.

OTOH people who are still themselves, in the early stages of the takeover, will certainly tell you of their own volition that the earring always seems to be right. Wearing it is presumably highly addictive.

The story doesn’t say whether they were wearing the earring while being interviewed

Is there more than one of these earrings? The rest of the story makes it pretty clear that it's a singular artifact. If so, and given that the other wearers certainly weren't dead when being interviewed, the only explanation is that some people just decide it's not for them and take it off. Leaving out the qualification "living wearers" would have left some wiggle room, but that's not what the text says.

It's one of those stories that sounds profound only until you start to ask questions.