And you're blaming the victim for not understanding things that were never explained to them until after they were already pwned.
The correct way to handle this would be for brainwallet software to generate and provide the user with a high-entropy passphrase rather than asking for the user to provide one. Failing that, it could at least reject very-low-entropy passwords (e.g. impose a minimum 20 character limit).
But even then we're band-aiding the underlying problem, which is that decentralization[0] and finance go together about as well as twizzlers and guacamole. Transaction reversibility is a feature, not a bug, and there's no trustworthy way to implement that sort of thing in a decentralized finance system. Absent a way to dispute fraudulent transactions the only way to avoid your money becoming everyone's money is to overcompensate on preventative measures: i.e. insanely long passphrases stored on hardware keys in lockboxes buried under a garden birdbath.
And sure, yes, we can point and laugh at the credit card industry for treating primary account numbers printed on the front of the card as secure tokens, taking decades to adopt EMV cards in the US, charging horrible swipe and chargeback fees to businesses, and so on. However, there is a reason why, a decade and a half in, people use credit cards and not Bitcoin. Credit cards actually function as a payment mechanism and you are less likely to be defrauded using them.
[0] I additionally dispute the idea that any cryptocurrency system is actually decentralized. The need to agree on the validity and order of transactions necessarily requires one individual or institution actually decide the rules everyone else, with unanimity, agrees upon. Operation of the network is nominally decentralized but the need for security against transaction reordering in the face of no strong identity being available means that practically, it is centralized.
We've seen this with the 'scaling wars' of Bitcoin. Two groups of shadowy puppetmasters - developers and miners - duked it out over absurdly stupid technical arguments regarding how to scale Bitcoin.