Maybe in some cases the "who are we to judge" phrase is used to  excuse and enable.   However  situations are not as clear cut as you would like.  Beware of  "rash judgement".
Those fixated on  "admonishing" do more harm that good.

Think of some who keeps getting drunk, driving drunk, getting violent with his family, stealing to support his habit.  Simply "admonishing the sinner" and letting him know that he's on the fast track to hell is likely to make  him harden his heart even more.

If the person is an alcoholic, he is in the grips of addiction, he is not capable of "repenting" on demand.   You may blame him for starting to drink so much but you don't know what is behind it.  It could be that he has a hereditary predisposition to alcoholism.  It could be that his life has had so much pain and suffering that without the anesthetizing effect of the alcohol he would have committed suicide long ago.

Mercy, empathy, discernment and intercession may be the better path.