Oh, I can totally relate to this, and I'm afraid it's only going to get worse as we approach November. To me the worst thing about it is how so many people are buying into this extreme stuff, in either direction. Why can't people just dislike a particular politician's actions or policies, without insinuating that he or she is the anti-Christ, or trying to destroy America? Culture of fear. Such a waste of energy, and disturbing to see how many people are stooping to this kind of thinking, and the resulting hysteria.
On the other hand, I've reconnected with some childhood friends I woud NEVER have found, or been found by, via FB. So this might be a bit time-consuming, but one thing you can do is click on the upper right corner of an offensive post, and choose the option to "hide" that story. It also gives you the options of unsubscribing from that particular poster, or to only see important posts (not sure how they determine that). That person will not be notified, and you can still look at their page if you like, but their stuff won't pop up on your page all the time.
I feel the same way... why do people have to get so hateful towards one another in regards to differing political views.... Insecurity or fear, maybe - like you said. I know about hiding posts, but it seems like too much work. LOL I actually signed off FB and don't plan to go back anytime soon.