This is one of those verses that can be a little misunderstood. We cannot judge people, God alone can judge people because only he knows the thoughts and feelings of each of us. Something that many people struggle with is knowing the difference between mortal and venial sin. It’s different to each person. For example, someone who struggles with alcohol addiction and gets drunk will not be as accountable as someone who doesn’t have that struggle. People with addiction have a physiological dependency on a substance. The person that doesn’t have an addiction does not have a body that requires them to drink alcohol in excessive amounts in order to operate normally. It is still a sin for both people because it is disrespecting the bodies God has blessed them with, but accountability is different. Only God can see the inner workings of a person, their struggle and triumphs, which is why he can be the only judge of the whole person. But we can judge situations, actually we should. It is through seeing someone else get too drunk that I choose not to drink and want to help my brother or sister in Christ. The next verse says that we will be judged according to how we judge others. I should want my brothers and sisters to point out when I’m out of line on something because it helps me grow as a person. I have struggled with social anxiety for years. It’s not healthy for me to just stay at home all the time and it is my friends and family who point when I’m becoming reclusive. We may not think of not wanting to socialize as a sin but there have been times in my life where it was crippling. We are social creatures, God made us for communion (hence Holy Communion) so when I cut that off, I’m preventing the love God desires for me. Sin can be simplified to the rejection of love. My friends and family can judge my actions in these situations and encourage me to get out and socialize. The gist of this is to say, we can’t judge people because we don’t know the depth of their struggle but we can judge situations in order for us to grow and to support our fellow creatures.