I totally believe most of facebook advertising is fake... but man you're damned if you do and damned if you don't when it comes to consumers.
Stop spending money on facebook and you will lose marketshare to those that do - even if much of it is fake.
Make a better website with no ads, no trackers, no popups and no distractions and people visit and leave quickly...
But.. if you do everything people hate, you seem to get enough conversions to still be viable.
I guess tl;dr - most consumers don't care and especially the ones who have money to spend. The ones that do care, don't spend money and certainly don't do so with any altruism to those places that respect their privacy/browser/sessions.