Human knowledge and intent matters in legal matters. If a technology is accidentally misconfigured to send sensitive data to a third party, and that third party knows that the data they are receiving was not intended for them, then they are still responsible for not willfully misusing that data. That's clearly the case with corp.com.
> If this is illegal, then I can shut down any site by sending my private data to it.
No, if you knowingly choose to send your data somewhere, then you can't turn around and blame the people receiving your data. Again: human knowledge and intent matter for the law.
As an example, a charge of trespassing depends on permission (human knowledge and intent), not whether you leave your gate open (how a system is configured).