Now you can argue that the right way to counter misinformation is by countering it with legit information, and that's certainly a valid argument.
But that idealistic approach quickly runs into a wall. As Bill Gates said on Oprah's show, "We were a bit naive: we thought the internet, with the availability of information, would make us all a lot more factual. The fact that people would seek out—kind of a niche of misinformation—we were a bit naive."
So yes, people seek out misinformation, because of some inherent belief that there is a vast conspiracy going on that they aren't aware of, and the more conspiratorial some news sounds, the more likely they are to believe it. So you can't necessarily fight misinformation with legit information, unfortunately. As a result, a public health crisis is likely if social media companies do nothing to control the spread of misinformation.