I’m responding directly to the OP, not to any specific response.
Your question would have no answer within the realm of traditional interpretation of Scripture. From my point of view, however, Scripture reflects to some extent the culture from which it came.
In parts of the OT, God gave Israel victory in war, and commanded genocide of his enemies. But over time the prophets thought he judged how the widow and orphan were treated, and they began to extend sympathy to those beyond Israel.
It seems likely (I’m following Bernstein’s “Hell and its Rivals” here) that hell developed as part of a vision of the afterlife as just, as opposed to everyone being shades. But that development was in a society where torture was used, and extreme punishment by God didn’t raise any eyebrows. Today, to a large part because of acceptance of Jesus’ attitudes even by non-Christians, it’s a problem.
Jesus called people to be his representatives in reconciling people to God and each other, but he also said that we would be accountable for how we respond. The accountability is as basic to his message as the reconciliation. After all, we shouldn't want evil to continue forever. That's not a kindness. Judgement means upholding the right and defeating evil. It needn't be envisioned primarily in rewarding the good and punishing the bad. A traditional definition of justice is giving every man his due. That's the concept out of which the concept of rewards and punishments in the afterlife presumably came. But I think a Christian can see it more in terms of bringing good out of evil.
I don’t believe Jesus ever encouraged unkindness. He taught that God was kind to his enemies and we should follow his example.
The question is how to understand accountability and judgement. That God should treat Hitler differently from a saint seems like an obvious implication of justice. But we don’t need to envision it in the lurid terms of Christian tradition. Perhaps we could use 1 Cor 3:12 as a model (though in the original context this passage was directed ato Christian leaders). To go beyond this I think we have to go to Unorthodox Theology, because we have to look at the intent of Jesus’ various statements about judgement.