>>280740166
>>280741128
To further tank OP's example, demons in Demon Slayer are corrupted humans often with terrible backstories that lead them to become this while demons in Frieren are biological terminators incompatible with empathy and laser focused on destroying humanity.
Frieren may coldly exterminate her enemy without sparing a thought their deceptions to seek mercy but that doesn't mean that she likes it, she hates demons for making her that way as much as the she hates them for their actions. That coexistence with them is in her view, an impossible goal, hurts her.
Simply put, Frieren would feel great empathy for the demons that Tanjiro fights but would ultimately come to the same conclusion he did and destroy them with a somewhat heavier heart then she destroys her own demons.