This. I'm used to politicians proposing simplistic, feel-good solutions to complex problems because most voters lack the critical-thinking skills to understand why said solutions wouldn't work. I'm surprised that Apple is doing it, though. Yes, I watch enough true-crime shows to know that many criminals are stupid and careless ("Hi, I'm Chris Hansen, and you're on Dateline! Did you really think you'd be meeting a 14-year-old girl here today?"), and I suppose some are dumb enough to store their child-porn collections in iCloud, but I assume most of them use other storage solutions and share photos on the dark web. Does Apple have data to the contrary? If so, where did they get it? The only way I can think is if large numbers of pedophiles who have already been caught willingly unlock their Apple devices for law-enforcement authorities, who then find their collections in iCloud Photos. In that case, the methods used to catch them (e.g., sting operations) already worked.
So this sounds like a combination of Apple bowing to political pressure and perhaps naively thinking that most people would be okay with the policy because no sane, civilized person thinks child porn is acceptable. Our culture does seem to view sex crimes as somehow more evil than other types of crimes. Most places in the US have databases of convicted sex offenders so you can find out if any are living in your neighborhood, but I'm unaware of comparable databases for convicted murderers, violent assailants, burglars, fraudsters, and so on. The fact that Apple has refused to unlock the iPhones of suspected terrorists and other criminals points to this double standard. Yes, they claim they have no way to do so, because of their stance on security, but somehow a security company hired by law enforcement found a way to do so in at least one instance.
I'll admit that, initially, Apple's announcement didn't seem like a big deal to me, and I didn't understand the uproar on this forum. The more I've thought about it, though, the more I've come to view it as something that will have little effect on the problem it's intended to address and that potentially will open the the door to abuse.