“As a writer, you should not judge, you should understand.”
Ernest Hemingway
I take this to mean people… of course… but also characters. If you don’t understand your characters (especially your antagonists), you’re in trouble. Because if you don’t understand them, your reader will not understand them, and they will put down your book…
But this is also about subjects. The worst case of judging is soap-boxing. We all want to avoid that.
But how about portraying the antagonists as evil or dumb? I tried that, it turned to crap. Instead, I try to do my best to make their actions and motivations as understandable as possible.
The more the reader goes, “that could be me in that situation”, the better… Even when they’re talking about the “bad guys”… (you shouldn’t be thinking of them as “bad guys” though, that’s just going to flatten and/or deflate your story…)