I think this is true of crowdfunding in general, isn't it? Anyone can start a crowdfunder, and say it's for a good cause, and it's not regulated at all afaik. Donors can report fraud to the crowdfunding platform, but it's up to the platform to decide whether they get a refund. Caveat emptor.
I think people need to be more aware of what a registered charity is. The Good Law Project is not a registered charity, therefore they are pretty unaccountable. If someone wants to donate to a person or organisation which isn't a registered charity, they need to realise they're taking a risk. For example, regarding vulnerability, charities would have a policy on vulnerable donors, and they are accountable to the Fundraising Regulator and the Charity Commission. That said, it's not black and white - vulnerable people are allowed to spend their money in many ways that we may consider unwise, and making a donation to a cause they believe in might give them a sense of reward that outweighs the cost. And as for foolish people - well, you know what they say about a fool and his money - I have limited sympathy.
I do think, with the Good Law Project, that Jolyon is a true believer with a Messiah complex, rather than a cynical scammer.