The posts are not intended to convince anyone. They are to signal tribal loyalties to people who already agree with you, while you marinate in your own sense of moral superiority.
Then further on says:
If these factions want to convince other people, they’re going about it all wrong.
It took me years of writing on the Internet to learn what is nearly an iron law of commentary: The better your message makes you feel about yourself, the less likely it is that you are convincing anyone else. The messages that make you feel great about yourself (and of course, your like-minded friends) are the ones that suggest you’re a moral giant striding boldly across the landscape, wielding your inescapable ethical logic. The messages that work are the ones that try to understand what the other side is thinking, on the assumption that they are no better or worse than you. So if you are actually trying to help the Syrian refugees, rather than marinate in your own sensation of overwhelming virtue, you should avoid these tactics.
I agree! Unfortunately it is all too easy to cast those who disagree with you as having questionable (at best) morals and intentions. It’s also too easy to talk in prepackaged catch phrases that are readily accepted by those who agree with you but fall on deaf ears of those who don’t. The end result isn’t a true debate or civil conversation but pontificating and posturing. I’ve said a number of times here that it takes a lot of work being objective when thinking things through. It takes even more effort trying to fathom how someone else reached their conclusions then trying to explain your position in terms that the other person is more likely to understand or accept. I’m not saying they will agree with you but they could come away with a better understanding of your position. I can speak from experience that the method McArdle recommends makes more of an impact than just lobbing verbal hand grenades at each other.
Read her entire article. McArdle doesn’t go into specifics on how you can fashion your position in a way that someone who disagrees will understand. For a start in the right direction I continue to highly recommend Arnold Kling’s The Three Languages of Politics. For a more theoretical approach check out Jonathan Haidt’s Why Good People Are Divided by Politics and Religion.