Is this just getting press because it’s Facebook? Anyone that works at a company that runs a proxy server to access the Internet should just check the referrer fields leaving the company for requests to sites like Gravatar.
It's getting press because it is siphoning off the page contents which include the names of files you have stored. It is quite a different scenario than just loading an image through an img-tag (which can be controlled through things like Referrer-Policy these days)
In the instance maybe, but the effect is similar over time. Both of these have effective countermeasures.