[WorldMaker]

It's not power, it's volume. Groups like Collective Shout are "squeaky wheels". They send enough letters/phone calls/emails to a payment processor, often via the company's legal team, often citing the processor's own terms and conditions, until the company caves from essentially peer pressure and takes all the whining and pushes it back onto their customers (vendors like Steam and Itch).

It doesn't take a lot of people/very big organization or a lot of money to do, just a willingness to be loud and obnoxious, but in a legal way.

It's the same thing with DMCA trolls that send takedown letters to demonetize things like YouTube channels. They don't need a lot of people/power/money, just a willingness to complain in volume and leave the evidence and fact finding to other people and/or automated systems like YouTube's auto-DMCA.