As per Vedic Scriptures, we should not call anyone a sinner because:
1. If he or she had not committed a sin, the bad effect of committing the sin would reach the person who called him or her sinner.
2. If the person had committed a sin, the half (50%) bad effect of the sinner will reach us.
3. By keeping quiet you do not attract any sin.
This rule in Dharrmasastras is based on God is dwelling in everyone and divinity is the essence of all beings.
However the concerned persons namely Parents, King, (Police), Teacher (Guru) and Doctor only have right to enquire or judge about any one’s sin or bad activity and punish or advise or correct as the case may be. Others do not have the right.
A story from Dharmasastra
Once three brothers were traveling separately on celestial vehicles to Heaven.
They saw a Garuda killing a serpent on the way:
First brother said, “It is sin”. His vehicle fell down to earth. Second brother said “Garuda please. Kill”
His vehicle also fell down fast. The third one was neutral and kept silence. He reached the heaven.
Therefore please stay from judging or condemning people for your own inner purification and increasing virtues.
In the Karmic Cycle, we will never know the reasons why certain things happen. Good things could happen to those who do wrong; similarly, those who do good, could undergo negative experiences. This is because, what we experience currently, could be the results of good/bad Karmas of past lives or even good/bad Karmas in this one and therefore, how can we judge something or someone based on what we see before us now?
Self-righteousness is a mental affliction (disease) caused by spiritual egocentricity. It amounts to a secular type of love that flourish under conditionality, one in which is only existent after an individual meets the standards of the condemner; oppositely, unconditional love is Divine or selfless love (prema bhakthi) because unselfishness is God.
So, Never be JUDGMENTAL.
Hope it is clear.
GF’ Blessings. OM Tat Sat.