there's a distinction between abuse from a third party and outright lying on the part of fb. suggesting that deleting data leads to nothing more than a CSS animation is asserting the latter.
I think the reality is that data will no longer "look" like it's in the data download, I'm sure FB will keep it to continue performing ML algorithms to pursue more and more ad revenue. Hopefully they will at least remove the code that is collecting it so that it stops in the future. No tin foil hat needed to believe this route.
“Delete this (from my visible feed)” might be the effect that you see, but that doesn’t mean it’s not still being used to feed your advertising profile or shared in some way with third parties.