I know some people who have more than one account. They have one account that has "everybody" as friends and another account for Real friends. If you didn't want to unfriend people, you could start another account and not have them as friends.
Also, you can Hide them in your news feed, without unfriending them, so you don't have to see their posts.
Or, you could just unfriend them. No shame in that - someone somewhere suggested a National Unfriend-Without-Guilt Day.
