You're only emphasising the legitimate use of "useds" by RMS. The notion, in any case, is that being a used of Facebook undermine's one's claim to privacy. Potatoes and cars don't apparently do the same thing, so they qualify as red herrings at best - having no relationship or bearing on the larger claims RMS puts forward.

C'mon. It's no secret that Facebook doesn't give much concern to users/useds privacy. Any claim to the contrary is highly suspect.

This is only to reiterate that the target market of Facebook does not include those who wish to maintain a greater level of privacy by not using it.