>>149361985 (OP)Aside from the mentioned Reverse Flashes, most of them are simply turning to crime or illegal activities as a necessity, not a philosophy. Simply put, they're not psychotic to begin with.
There are benefits and disadvantages to this, it means as said that Flash can reason with them or they can reason with each other, but it also means they're less susceptible to being duped or dissuaded through some character quirk.
And I didn't want this to be a A vs B thing, but in hindsight I realized their pragmatism was also why it felt reasonable for Captain Cold to associate with the Justice League professionally, since it's all business, compared to any amount of leeway with Harley Quinn who even during her redemption arcs is still visibly unstable.