You are missing half the quote, "I really wanted them to hurt the kid. I could taste it. Then somewhere deep in my brain, an alarm went off: this isn’t good for

You are missing half the quote, "I really wanted them to hurt the kid. I could taste it. Then somewhere deep in my brain, an alarm went off: this isn’t good for me. I’m becoming something I don’t want to be.". His point is the exact opposite of what your truncated quote suggests.