Is there any examples of people legally going after Visa or Mastercard?

I have a feeling this is just PR by the many examples I've seen of them doing this recently. The legal stuff just sounds like cover.

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.

But this does send shivers to the small business owners who have nothing to do with porn. The fact that they can be de-platformed by Visa on moral or political grounds.

What happened to PH push to accept bitcoin?

Oh no doubt. This is becoming a very scary development as services. Demonetization and deplatforming happens over increasingly harmless activity is a serious problem going forward into the future.

Like all monsters that get created no one cares because it's used against the 'bad guys' so no one cares. And then it just becomes normal.