There is literally no debate. Authoritarian elements want to look through your stuff because some people do bad things. I'm at a loss, to me nobody should even have to justify why the answer is no, it's a principle of natural justice.
Its pretty screwed up when the onus is on people to explain why this is a bad thing. The correct action is really just to walk away.
Yes, you should explain why something is bad, or else we are just doing things based off of how we feel… does that sound better to you?
The correct answer should be that the most well reasoned argument should be supported. And we should not expect anyone to intuit the best answer - repeating it as much as needed.
Also I think they should have to face serious repercussions in countries with strong data protection laws, should they decide to unilaterally change terms of service for their users in these jurisdictions, to reserve the right to search their devices for illegal images.
For many people heavily invested in their ecosystem, it’s also not that easy to just walk away. For other users, the alternative (Google) is not necessarily more trustworthy.