When you judge another, you do not define them, you define yourself. (Wayne Dyer, self-help, best-selling author)
When we are tempted to judge someone, we must be careful to limit our effort to an evaluation of their work or their words, not their character or motives. What they say and do will reveal their character, so we should let that be the evidence without our judgment. As Dyer suggests, our judgment of others really reveals more about our character than theirs.
In the same way you judge others, you will be judged, and with the measure you use, it will be measured to you (Matthew 7:2).