The concern wasn't about ads, it was about patient privacy. You guys basically put together a search engine for medical encounters, allowing physicians to access medical records they shouldn't be able to: https://www.wsj.com/articles/behind-googles-project-nighting...
Can you elaborate more? I don't believe the search engine produced did not let physicians access anything they weren't supposed to. This is well stated in their public documentation.
The feature which seems to be freaking people out is sound-alike searching based on patient name. This isn't a new feature at all; it's been specified as an optional feature in the DICOM standard for literally decades.