above the law?

James 4:11-12

The key words are: judge/judgment (if you stare at those words long enough, they look really strange!) and slander/speak against. James says that if you slander your brother or sister, it indicates that the law "Love your neighbour as yourself" does not apply to you and that you are somehow above the law or are indicating that the law is invalid. James reminds the reader that there is only One who has that kind of authority.
God is not subject to the laws he gives us. While the law is a reflection of his character and personality, God is only "subject" to himself. He only answers to himself. I am subject to the laws that God gives me. I am a judgmental person. When I judge others, I am not only looking down on them (as if I have a position higher than they), I am looking down on the law (as if the law answers to me rather than me answering to the law).
Some people are quick to quote the verse "Judge not, lest ye be judged" (I love how that verse is always quoted in the KJV) but this does not mean that we, as followers of Jesus, should not point out sin in other people's lives. It does mean that we should do it out of love, recognizing that we are no better than they are and not above them in any way.