Picture this. Let's say you make formstr use Tor exit notes in a way that makes it impossible for any relay to track your user. Great. Formstr is now truly private. But you sold Nostr itself as private, not formstr.
Then your user switches over to another form client that doesn't use Tor and now all his privacy is gone. They will blame the protocol, nostr itself, for leaking their data and will never use any other nostr tool ever again.
The protocol cannot guarantee privacy. Only formstr, as a product, can. We cannot lie to users or it will bite us in the ass.