I think (most of them|they) should be.
While I feel that a myriad of tags is useful for some larger sites - Google in particular, where each tag usually refers to a separate app which comes under the Google brand - I don't think that the majority of these Facebook tags are really useful, since they come under the singular Facebook application - while Google Docs and Gmail are two distinct applications, Facebook pages and Facebook groups are a small part of a much bigger app.
One tag of note (possible saving), however, is [facebook-connect] - since it can be used as a method of authentication for sites other than Facebook.