@MoeBritannica of course the answer to that is the analytics

those 'like this on facebook' come with a payload of javascript to spy on the user and it's cheaper and easier for companies to outsource the spying on users of their website to NSA/meta/facebook (and their army of adtech advertisers) than to implement a similar payload themselves

also if the big javascript blob that is spying on you is from some skuzzy porn site you might block it but who's going to block all of facebook?