Judge not, and ye shall not be judged: condemn not, and ye shall not be condemned: forgive, and ye shall be forgiven: Luke 6:37 KJV
Only God knows the why.
What we sow we reap.
This is an unalterable kingdom principle. Being judgmental brings a harvest of judgment. A condemning attitude will bring forth a harvest of being condemned.
Why people think like they do, act like they do, and say what they do is only known by God. He, and He alone, is the Righteous Judge.
To be forgiving is to walk in love and that will bring a great harvest of love and forgiveness.