I have people on my ignore list here. I am not opposed to opinions which aren't my own. But I can be extremely opposed to the way those opinions are delivered. I see no particular need to concern myself overmuch with people who are abrasive, abusive or unnecessarily aggressive. Those types tend to push buttons in me that allow me to give myself permission to be someone I don't wish to be, and since nothing will be gained from interacting with them, I choose not to engage with them.
I also have people on facebook that I am friends with, but do not follow. Generally it's because they are prolific posters but post crap I'm not interested in. On rare occasion, it's because they post crap I don't want the rest of my friends exposed to through me.