I've been giving the OP a lot of thought, and came to two conclusions:
1. The OP is predicated on the idea that unfriending or blocking a poster is indicative of being less tolerant. That actually is not true.
Just because I don't care personally to hear your opinion does not mean that I would deny you the right to have that opinion. For example: I'm fairly supportive of protection from descriminiation for homosexuals. However, I don't feel the need to watch Will and Grace or Modern Family simply because of its positive portrayal of homosexuals. I'm also supportive of Rap Music thanks to my support of freedom of speech. Doesn't mean I listen to it at all.
Conservatives on the other hand are often happy to seek out that they disagree with. However, their goal isn't to learn, but to bully and beat down or characterize as Unamerican.
There are folks on this board I've blocked. The reason why is that no matter what is posted, their reply to the topic at hand is always devoid of substance and always involves personal attacks. If they have nothing to add to a conversation, why bother reading them? There are a few posters I could name by name that if I grabbed their last twenty posts I guarantee that 18 or more of them would involve nothing but name calling, racial slurs, and gripes about marxists commie pinko homo leftists. Why bother? That leads to the second point....
2. If a person is wrong, refuses to learn, and denies everything when presented with facts or is otherwise vulgar, why should I put up with them?
I recently did unfriend two folks on Facebook. The first posted an image of Rick Santorum made from a collage of images from gay porn. Seriously WTF. I have two kids. If they'd popped up behind me on Facebook when that post came up.... I mean seriously! WTF. I don't want to even have to explain that.
I support that person's right be mad and offended at Rick Santorum. I Support whole heartedly their freedom to express that anger. I don't have to read it. Biblically you're only supposed to focus on what is pure, holy, and upright. I don't have time for gay porn in my friend feed.
The other person repeatedly posted birther nonsense. The whole birther thing has been throughly debunked. It essentially hangs around now as a way for racists to try to look slightly less "racist". If you're going to hold on to that view after it's been pretty throughly debunked, feel free to do so on your own time. Again, I support that person's freedom to be stupid and look stupid. I don't have to participate.
So if being unwilling to tolerate folks that choose to be vulgar or stupid makes me less tolerant, then fine. I'm intolerant. Truth be told the world could probably use more intolerance when it comes to Stupid.