I feel like a lot of the dislike/lack of grace/forgiveness towards Tartah and Custas comes from how little people care about the bigger picture. The bigger picture here being social and systemic injustice, which affects not just individual people/characters they happen to like but a large sum of people, many/none of which they know unlike Coco the mc and the other core main cast characters.
They seem super focused on individuals and only seem to care about said injustice if it affects people/characters they personally find easy to like. If they aren't as palatable and easy going and whimsical, they simply don't even seem to bother trying to understand.
Furthermore, if you view everything through such a hyper individualistic lense rather than viewing the actions of Tartah and Custas more as that of individual decisions and less as an expression of the accumulation of all those people that have been wronged by the system in general, then it becomes easy to dismiss and hate on them. Because they [these kinds of readers] don't see the pain of all those people we haven't gotten to see (within the main cast and only through characters like Tartah and Custas) but make up a significant portion of the society in wha. They just see two angry boys hurting their favs rather than the anger of years of injustice towards many from more socially precarious backgrounds.
