One of the dilemmas of social network sites like Facebook is what to do about all the people you knew at some point in the past and had lost touch with but that you were not uncomfortable about having “in the past.” Not that there is anything wrong with them or with you and, no offense, but they were just part of a different part of your life that has had its time, come and gone, and is not particularly relevant in the present. Nor am I any more relevant to their lives now since I am also a part of that time come and gone.
What does it mean to be somebody’s “friend” online anyway?
Rummaging About 
That’s what the “de-friend” option is for.
I look at FB as a very ephemeral thing in the first place, so I feel like it’s totally okay to let those reconnections with people remain very superficial. There isn’t much import to adding someone to your list of friends, and if you don’t want to hear about their goings-on, you can filter them out very easily. I don’t really expect meaningful reconnections with “long-lost” friends beyond the quick message or two. After all, if they were important in your life (and you in theirs), they wouldn’t have been “lost” if the first place.
Yeah, I’ve been reluctant to use the “de-friend” option. Seems rude somehow. And I end up doing a lot of filtering on this side of the keyboard just because of what I do for a living.
As you said, Facebook is also something that likely will come and go, so it really isn’t worth getting all that worked up about.