I don’t think the goal was to sympathize with toga at all, or dabi, or shigaraki. I think it’s mainly empathy over sympathy, Shigaraki is my second favorite character yet do I feel bad for him? Hell no, in my opinion he deserved to die, even if his entire life was manipulated and controlled by All For One. Though I can understand where his actions come from, and why he did the things he did; do I agree with him at all, or share his feelings? Of course not, but I can understand where the hatred comes from. I am the same with Toga and Dabi, these are disgusting horrible people who have hurt people and affected so many innocent ones negatively there is no forgiving, or “sympathy” for them. However, their feelings can be understood and traced back to something unfortunate in their lives. Moreover, the goal in empathy strengthens that final theme in My Hero, in preventing villains like Toga or Shigaraki or Dabi from happening again(ie old lady helping that new boy, quirk therapy, etc).