Y'all are starting to make me more sympathetic to Apple. Their biggest misstep was making these announcements simultaneously without foreseeing how many people would (willingly or otherwise) conflate them.
This is not true. There were multiple features announced. iMessage data is not being scanned by most phones. The ONLY CSAM detection that happens is on photos being uploaded to iCloud Photos.
The only phones where iMessage photo scanning happens are those for children under a certain age (maybe 13?) whose parents who have opted into child protection where the phone scans for nude photos and notifies the parents.
People are conflating these two _different_ but _related_ features and their goals and limits.