I think it is because people are generally NOT saying that they should necessarily BLOCK things, but instead label them appropriately.

THIS IS SATIRE: at the top of ONION articles. THIS IS FAKE: on top of us-political-truth-grabber-buzz.com

maybe OPINION gets added to HUFFPO

I think that would likely be enough to satisfy most of the needs.

... Although while we're talking blue sky / greenfield ... maybe we add something like:

   Here's How Ridiculously Expensive It Is To Replace A Windshield On An Aston Martin |[ $4414.41 ]

to all that shitty clickbait out there :)