>they have no right to

You seem to be confusing what feels intuitively wrong with what is actually unlawful. Law doesn't work on feelings. Where are the terms of use? Do they explicitly prohibit this kind of access? How do they define it?

If a website publishes data and provides a public key that automatically allows a browser to retrieve it, good luck arguing that your "security" was bypassed.

Also, OP mentions confidential information. That doesn't automatically make neathack liable. If I publish someone's medical records in a publicly accessible comment here, are you liable for reading them, or am I liable for publishing them on a website with essentially no access controls?

>an actual leak

Got a link? Or "just trust me, bro"?

>I would bet a sizeable amount of money

Unfortunately, my religion prohibits gambling, which we consider degenerate behavior. But by all means, keep the confidence. It would be even more impressive if it came with an actual legal argument.