If they were scanning images that were uploaded to icloud on Apple's servers, no one would care. iCloud is not encrypted and Apple provides governments access to iClod data, everyone knows that, and other cloud providers already scan content for CSAM material. The difference is that Apple is doing this scanning on your phone/computer. Right now, they say that only images that uploaded to iCloud will be scanned, but what's to stop them from scanning other files too? There's been a lot of pushback because this is essentially a back door into the device that governments can abuse.