[sixstringtheory]

If you've stated your preference to them and explained why you personally don't feel comfortable using Facebook, and they don't care, then they are the one being unfriendly.

Of course there are many ways to state that preference, ranging from "you're an idiot if you want to keep that advertising agency alive" to "I don't feel comfortable putting details of my personal life, including our friendship, on the Internet for private companies to profit". If someone truly belittled the second, then yeah, they aren't a friend.