Pro tip: I saw a guy at a Denver meetup argue that the moon landing was faked because of the flag waving.
He kept saying the flag moved in the video, so there must have been wind. I had to point out that NASA itself explained the motion came from the pole twisting as they planted it, not air. This was in a room with about 30 people, and half of them still looked unsure. How do these basic debunks not stick with people?
You're right about it being like bad ads. I see it all the time with those fake news stories my sister shares. The headline just confirms what she already feels, so she hits share without a second thought. It's that quick, gut reaction before logic even gets a chance. We're all a bit wired to go with our first feeling, especially online.