This may sound silly, but I think saying "you support this because you are a bad person" isn't very likely to convince people to change their minds.
For instance, coloradoatheist gave what might be the motive for some disagreeing with this. Is he lying?
I've noticed a lot of libertarians and conservatives banging on about this concept of "Please don't call me mean names or you'll never convince me of anything." Here's a clue. They're not going to be convinced anyway. They are closed minded. Partisanship is, like it or not, more of a problem on the right than the left. As is fake news. People have tried to charm them, cajole them, and even (gulp) compromise with them. They're having none of it. Most of them are heartless bastards. Those that aren't heartless bastards are enabling heartless bastards by supporting zombie economics and ideology that is damaging to the human condition. They won't like when you point this out, after all, no one likes being forced to look in the mirror. The same can be said for Trumpies that talk anti-semitic, talk about building walls and kicking out illegals, support Blue Lives Matter, and then get all pissy because you call them racists. Know why? Because they're fucking racists. No amount of reasonable discourse is going to make most of these people change their racism. That leaves you only one way to fight it. Call it out for what it is and give an alternative view. Counter them, and when they bitch and moan about being called names, keep reminding them that what they do to everyone else is by far, much worse.