How about creating WTFPL-inspired license? If you do not need any other restrictions, just take the most permissive license and define what user can not do. "Do-anything-you-want-except-blockchains public license" may be a great fit for your needs.
What you are looking for is not an open source license.
That’s an oxymoron.
What is the context to your request? I ask in theoretical terms. Is it so ridiculous to assume a genuine good coming from a blockchain-related project, provided we are referring squarely to the technology of a decentralized and distributed ledger? Technology like this doesn’t belong to scammers and swindlers, they simply exploit it they way they would have any other technology I’m trying to understand your concerns