garbage engagement are posts so obviously wrong/provoking/you name it that you must exercise supreme self control to not engage with the content. And for some people it is quite difficult to do so algorithm thinks that, hey this is trending so might be i should show this to more people. So this garbage turns up on your stream. I bean dealing with this by straight up blocking such accounts, but this is loosing battle in the sea of bots :)

Person A: Says something exceptionally inflammatory and provably false

Person B-Z: That's a horrible thing to say, why are you like this?

Algorithm: Wow, this post must be awesome, I should show it to more people!