if you're attempting to keep the information private, you're not doing a good job by handing it to a third party.

Expectation of privacy is kind of based around self-incrimination, and you lose a lot of those when you hand information to a third party.

Even if it's "public" (in the legal sense of 'not protected'), Tor can be useful against non-state actors, or against weaker state actors.

I'm not saying there isn't a colloquial expectation of privacy, but that the jurisprudence on privacy doesn't apply to Tor (or at least, that there is an argument that it doesn't).