Evidently there are many people who don't understand what Jesus said, in context.
A woman who was caught in the very act of adultery was taken to Jesus in an attempt to gain advantage over Jesus. (She was caught IN THE ACT. They had BOTH the man and the woman involved - but let the man go free. They didn't care about righteousness - they wanted ammunition against Jesus.)
Jesus' detractors, the religious leaders of His day, said that the law of Moses called for the LITERAL STONING TO DEATH of those who were guilty of adultery.
They thought they had Jesus in a trap. If Jesus said, "Don't stone her" then they would accuse Jesus of breaking Jewish law.
Conversely, if Jesus had said, "Stone her" then Jesus would have been in trouble with the Romans for breaking their laws.
Instead, Jesus said what He did: "He that is without sin among you, let him first cast a stone at her."
Of course, none of them were without sin. They were guilty themselves, and their conscience convicted them. They all left.
He didn't tell people not to condemn unrighteousness.
So, when one calls another man a jerk for cheating on his dying wife, he isn't "casting stones."