Sounds like GCBTW is at it again, but even so, I don't think the feature needs to go both ways.

So you, personally, feel like <Player X> is no longer friend material or interesting or whatever. You unfriend them. Did you tell them even? What was your value to them? Are you unfriending just because you're in a, "fuck it all" sort of mood?

They might consider you their best or one of their greatest friends.

This just kind of reeks of undervaluing the meaning of the word friend, and that people are being added to your list and taken off of it, on day to day whims.

Like how many people on your lists are really friends if you feel this way? What's your criteria for adding someone in the first place?

Though I suppose, at this point, it doesn't matter at all. In Dawntrail you'll be able to remove them, then blacklist them, and they won't even appear as part of your game world anymore. Won't matter then, if you're still on their list.