I don’t know about you, but I use Facebook to maintain a connection with people on the periphery of my life — people that I’d still like to be able to get in touch with, but with whom I don’t have a strong, deep, ongoing friendship with. Sure, I sometimes post on a good friend’s wall and often like my mom’s posts, but Facebook isn’t my primary means of staying in touch with them or the other people who are really important to me. I write to, or call, or spend time with, or even send letters in the mail to the people who are really important to me. In general, I keep a big list of friends on Facebook just so I can reach out to any one of them when the mood strikes me — not because I regularly want to keep up with any of them. What I’m getting at, is that for me to defriend someone, they have to be a really marginal figure in my life, because Facebook “friendship” doesn’t hold a lot of value for me in the first place.
So I’m going to assume that you, too, defriended people who had grown so far apart from you that it seemed silly to maintain even that much of a meaningless and effortless connection to them. Good for you. Not everyone you encounter in your life is going to be someone you want to maintain a connection with for the rest of your life, and acknowledging that also frees you up to dedicate more time and effort to the real and lasting relationships in your life — the ones that matter to you offline, too. Facebook friendship isn’t actually friendship, or a relationship of any kind — it’s a bookmark for a person in your life, reminding you, “Oh, if I go here, I can reconnect with Xena again. Cool. If I ever want to rekindle our friendship, I know where to find her.” Likewise, terminating a Facebook friendship (especially with someone you barely know or speak to) isn’t terminating a relationship, it’s just acknowledging what is probably already reality: that you barely know this person anymore, and don’t see yourself growing close to them again in the near future.
That sounds like it could be pretty painful for someone to find out from a friend. But if the above situation is really the case, then the other person should have noticed you weren’t really friends anymore long before you terminated the Facebook connection. It’s not a personal attack (it doesn’t sound like you’re defriending people in anger or retribution, like an angsty teenager), though it might carry some of the bittersweetness of making you (and your former FB friend) realize how quickly time flies and how much people change. That’s natural. What’s not healthy is for that person to then throw a tantrum about it.