I don't know if there are examples of regular people going after those monsters (I don't think Visa/Mastercard are even afraid of this) for this or other reason

I don't know if there are examples of regular people going after those monsters (I don't think Visa/Mastercard are even afraid of this) for this or other reasons. The thing is that any legal action can be used as political lever. As a business you don't want to be in a position where you have to give excuses or negotiate. Hypothetically, the EU or some crazy US senator can say Visa is endorsing CP (even if it's not 100% true, but is good for the senator or EU parliamentary image), that they will engage in a full investigation and there is a possibility of facing sanctions. Now Visa has to activate a PR and legal campaign that can last years. It's better to just cut off that single website from the customer list.