When you join a Zoom session over the browser, you don't sign a TOS. And I assume that actual licensed medical establishments are under their own TOS provisions that are compatible with HIPPA requirements. Training on voice-to-text transcription, etc... would be a pretty huge privacy violation particularly in the scope of services like therapy. Both because there are demonstrable attacks on AIs to get training data out of them, and because presumably that data would then be accessible to employees/contractors who were validating that it was fit for training.
Out of curiosity, has anyone using telehealth checked with their doctor/therapist to see what Zoom's privacy policies are for them?
The UK, for example, has hundreds of private mental health practitioners (therapists, psychologists, etc.) that provice their services directly to clients. They almost universally use off-the-shelf technology for video calling, messaging, and reporting.