Doesn’t matter that it was obtained “independently”.

Doesn’t matter that he didn’t sign an NDA with Okta. Zoom certainly had agreements with Okta that prohibit employees from either company from sharing private information publicly like this. To remain compliant, they can’t continue to employ someone who is publicly violating that (with his handle emblazoned all over the documents, no less)

You can’t expect to work for a company while publicly leaking materials from one of their partners, regardless of how you acquired it.