I think I know what happened - this is the fallout from iPad facebook story.
On day one of iPad there was some app called "Facebook" for $3 which wasn't really the app from Facebook itself, but some dude making a quick buck. Apparently some big wig then issued instructions "clear up our name usage on iPad/iPhone" and someone else implemented it via
SEND_TAKEDOWN_NOTICE(query("SELECT * FROM apps WHERE name LIKE '%facebook%'")).
Apple will do the basic, honest attempt to prevent trampling on others trademarks but it's not an outright bannination.
In general with social networking its a gray area - if an app is a twitter client does it have a reason to have "twitter" in the name? It surely does. If I was Apple I would promptly react to mark holder complains rather than proactively deny things.
I would also make exception for major marks - I would contact them proactively and ask for guidance. And then if I was Facebook from before the iPad incident I would say "it's cool, let it slide - we'll deal with it later if there is ever a real problem".
Facebook is relentlessly and constantly capricious with its API users. This kind of thing is an every day occurrence with them; if they're not doing it on purpose, they're doing it by accident because they don't appear to test their own APIs.
On day one of iPad there was some app called "Facebook" for $3 which wasn't really the app from Facebook itself, but some dude making a quick buck. Apparently some big wig then issued instructions "clear up our name usage on iPad/iPhone" and someone else implemented it via
SEND_TAKEDOWN_NOTICE(query("SELECT * FROM apps WHERE name LIKE '%facebook%'")).