Well it is of course not possible to 100% prove that Tor protects your privacy.
But the lack of evidence is also evidence. While we have evidence that the gov was able to identify indiviuals using Tor e.g. hosting drug portals, there has been no reports that individuals or companies are able to de-anonymize Tor users.
How do you really know that? I understand the theory, but do you have evidence? Have you tested it or read research that has tested it?
I would hesitate to give advice to people when they could get hurt.