> Put a banner up. Identify it with Mr Yuck sticker. Don't remove it as if it never existed. That's dangerous, no?

You misunderstand how wrong information, identified as such, is received.

https://www.politico.com/story/2017/09/11/facebook-fake-news...

Pointing out something is false either has no effect, or makes people double down on wrong ideas / beliefs. Continuing to host said ideas will cause them to spread.

The responsible thing was removal, but perhaps with more transparency around how and why.