Why do people Judge?

I mean we dont know anyone's cirstances. Lets take for example someone who has been in an abusive reltionship, wondering why they deserved that and are in need of help. If you didnt know what happened to he/she, for them having such an average mood since you dont know their past. Should You judge them? or is it that the unconditional love you may share with them will bring much needed joy to their Spirit. Similarly now we do not know cirstances of so many people around the World. So why is okay to Judge and not to Love?