? When your message is readable on the other side, on the app which we are supposing has a "problematic" privacy policy, it is unencrypted. Encryption is a matter in transmission. The data acted upon (e.g. displayed) on the other application has to be finally unencrypted, or decrypted.
Alice sends message "Hi" to Bob through app Alpha; it is encrypted during transmission; Bob receives it on his app named Beta - but Beta manages the message in fully readable form, "'H'-'i'", and does what its coders want with it.
I should remind you that your application and their application will share your messages but may have very different privacy policies.
(Some problems will persist and still require further assessment and decision and possibly division.)