Unfortunately, they don't use only these addresses. Right on the first page I have missing images from scontent.fprg2-1.fna.fbcdn.net, which I guess is some local cache, and the IP address belongs to different subject.
THAT is the big problem!
A webpage is not a single file that is downloaded from the server pointed by the domain name you enter.
It is not like your device makes a connection to facebook.com and then receives some big file containing an image of what you see there.
Instead, a webpage consists of many different elements (HTML text, stylesheets, scripts, images etc) and only the topmost file comes from the server you visit, all the others can (AND DO) come from different servers, often even things like "Content Delivery Networks" (cdn, as you see in the fbcdn in the name above) that not necessarily are from the same company that serves you the website.
This makes it "very difficult" (or maybe "impossible") to do what the topic starter wants, as I already wrote.
Blocking is similarly difficult, but there you have more chance because you can block a single very important item (like the toplevel HTML file) that makes the entire page unusable, and the user thinks the site is blocked and goes off doing something else. Hopefully.
(but a technically more advanced user will know tricks to fetch the site through other intermediates, like proxies or VPN, to work around that)