The "regulations" are a red herring. It's the "or else" part that's not being enforced.
As an example, Wachovia (now part of Wells Fargo) failed to follow US anti-money laundering laws. You or I would be doing HARD TIME for such violations. Any Banksters at Wachovia or Wells Fargo? Not so much...
How a big US bank laundered billions from Mexico's murderous drug gangs
You’re right. It is a big mistake to defend the big banks. They would never have gotten so large in a free market. They are a few of the winners chosen by government policies.