I was listening to terrestrial radio the other day and was surprised to hear a radio advertisement beckoning retirees to cash in their 401ks to join the cryptocurrency future of Bitcoin and Ethereum. The bubble is too big for Google to slow it down and it has grown beyond the realm of tech savvy geeks into something fueled by hype and hubris.
Google doesn't want to slow it down. They just don't want to be associated with companies that are related to fraud. And, I think that this is a valid and correct choice for Google because they have their own brand to protect.
More specifically, Google doesn't want the SEC to hold them liable when they go after some of these fraudsters.