Let's stop for a moment and consider how the web actually works. Your browser sends an HTTP GET request for a page. The response for this page contains HTML and JavaScript. The browser then executes the JavaScript, often making other requests (GET and/or POST) in order to do its work. In the case of most Facebook operations (I haven't looked at this one specifically), JavaScript executed by your browser makes these requests on your behalf to communicate with and display information from Facebook. Google Analytics works this way too, making additional requests to a different server from the page you directly requested.
Unless the website in question has a back channel directly to Facebook, through which it communicates information about the GET requests you've made, the initial GET request has nothing to do with the data sent to Facebook. Furthermore, because of browser security limitations, this back-channel approach is not always even possible, since the original site does not typically know your Facebook ID (this may not be true for some sites with which Facebook has special partnerships, e.g. Yelp and TripAdvisor). Only requests made to facebook.com would have the cookie information that identifies you.
In summary, the HTTP GET request you make to fetch a web page has nothing to do with the information sent to Facebook, and HTTP's recommendations about GET requests have nothing at all to do with these other requests.
Also, people have been senselessly abusing HTTP for years.
Unless the website in question has a back channel directly to Facebook, through which it communicates information about the GET requests you've made, the initial GET request has nothing to do with the data sent to Facebook. Furthermore, because of browser security limitations, this back-channel approach is not always even possible, since the original site does not typically know your Facebook ID (this may not be true for some sites with which Facebook has special partnerships, e.g. Yelp and TripAdvisor). Only requests made to facebook.com would have the cookie information that identifies you.
In summary, the HTTP GET request you make to fetch a web page has nothing to do with the information sent to Facebook, and HTTP's recommendations about GET requests have nothing at all to do with these other requests.
Also, people have been senselessly abusing HTTP for years.