But the tool in the article is to ask people whether they think a certain headline is accurate and then looking at the effect that has on their sharing of other

But the tool in the article is to ask people whether they think a certain headline is accurate and then looking at the effect that has on their sharing of other articles. If someone with the "I am right and you are wrong" mindset shares fewer articles they think are not accurate, they'll actually be right more often. (At least in their own opinion.) If this gets weaponized to make people on "both sides" pay more attention to the accuracy of what they're sharing, I'd expect that to result in a more healthy public debate.