The mechanism that I suppose is at play here: Humans’ ability to spot something “of interest” has been honed through tens or hundreds of thousands of years of primate evolution. But if you THINK about it, you tend to see what you think you ought to see. Zen has it right… sometimes: “No mind” can be a pretty good way to operate.
My own touchstone, which I do NOT always manage to use: If a story, picture, video… makes me angry about how wrong it is or if it fits my preconceptions very well, I try do do a bit more research. If it’s “meh” or even “huh, THAT’s interesting” I usually don’t bother.