Villains in The Dark Knight are:

The Joker whose backstory is not known,

Two Face who was a district attorney,

Salvatore Maroni who is a mafia boss,

and guest appearance by Scarecrow who used to ve a doctor at Arkham Asylum.

So when you say

Most of the villains are literally people who worked for Wayne Corp. that suffered accidents on the job due to terrible working conditions.

What the hell are you talking about?