The idea isn't so much that we judge, but more about, who the hell do you think you are to judge someone else.
Here is the verse in context:
Matthew 7:1-5 1 “Do not judge, or you too will be judged. 2 For in the same way you judge others, you will be judged, and with the measure you use, it will be measured to you. 3 “Why do you look at the speck of sawdust in your brother's eye and pay no attention to the plank in your own eye?
verse 1. tells us what not to do.
verse 2 gives us the modus operandi of judgment.
verse 3. points out the hypocrisy of someone that has the nerve to condemn someone else.