I unfriended a few folks during the election season for the same reason -- hateful posts. A couple I just hid or unsubscribed from their feed for the time being. I have also been unfriended by a few folks, and it does kind of sting when you realize they've done it. There are probably a few I don't even realize have unfriended me.
One way to find out someone unfriended you is if you go their Timeline, and instead of saying "Friends" it says "Add Friend". Or if they show up in the right-hand column as "People you may know". But you can't please everyone, and some people friend others for the wrong reasons. I have accepted friend requests from people I don't even remember just b/c they went to the same high school or we used to work together years ago, and if they bug me or post ugly stuff, I don't have problems unfriending them as we were not really connected in the first place. I have also friended or accepted friend requests from people I've never even met in person but we share an interest and have interacted in a FB group, and they seemed like nice people. I've "virtually met" some really great folks that way, actually, who share a lot of the same interests.
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow