I have found personally that those who are worst at believing and forwarding misinformation online are in their late 40s and 50s-young enough to use technology,

I have found personally that those who are worst at believing and forwarding misinformation online are in their late 40s and 50s-young enough to use technology, but old enough to have not learned how to deal with a deluge of information. This doesn't apply to all older people, of course. But on aggregate, I would agree with you.