People can be mean. Really mean. If you doubt this, spend a little time reading the comments on just about any news story post on social media.
What we tend to forget -- or ignore -- is that the people who are the subject or target of these comments are human beings, and thus capable of being hurt by such comments. While there are boors out there who would, yes, say these things directly to someone's face, I dare say the vast majority of negative commenters do so because there is distance between them and their target. Sure, you can click on their profile and learn more about them, but for the most part, we don't do that. Or if we do, we still really don't know who they are.
I'm not saying we shouldn't share our opinions or even get into a civil exchange with someone on social media. What I am saying is that we all need to make an effort to take the high road. I believe in advocating for a position without tearing down the other side. We can campaign for our candidate without ripping into the competition. Think about the last time you had your mind changed on something. I'll bet it wasn't the result of someone harshly criticizing you. Especially someone you didn't even know. In fact, it may have had the opposite effect.
I have many friends who are public figures and get angry when people who don't know them, have never met them, and don't know anything about them as a person will skewer them in a comment post. If you disagree enough to make a strong statement, take it up with them directly. In person. Be brave enough to engage in civil discourse face to face. Who knows, you might learn something.
My challenge all of us is this: think before you comment, think before you post, think about the person you may hurt with your words. Put yourself in their shoes. Then adjust your sentiments accordingly.