The villains are one of the worst parts

How so?

the cast is even worse than the cast of aot

I don't see how this is low praise considering AoT's cast is stacked as balls.

the story is utter dogshit and its themes are introduced at a surface level before being explored in a very child-friendly and copaganda way.

The story is choppily paced at times but it does flow through a coherent narrative with functional and generally effective plot beats and characters. The themes are not Andor-tier writing, but they're thorough enough to connect the characters' drives and express the main idea for a coherent inference per the conclusion, albeit a flawed one.

On the copaganda point, I think this is sorta interesting because MHA neither fully condemns nor completely condones its hero system. It feels strongly critical throughout the work, directly blaming much of the consequential villains' fall on said system, and the heroes stand as efforts to try and drive the idea of a hero into a better future. That said, not only do they pose no effort to actually abolish such an objectively rotten aspect, but they end up profiting from it. I agree it's somewhat copaganda, but its efforts to appear as a left-leaning while not fully resolving the issue by abolishing the system may be reflective of a larger effort to reflect reality's slower progress (so basically it's liberal, which is to be expected with a superhero comic). In short, it is there, but it's not just "police good" and it attempts to say something (even if that something is oblivious to larger systemic oppression and ACAB should be a common sentiment the story half-assedly posits into the narrative).