The "screeching minority" memo gives some insight. Let me break it down line by line. This is just my personal opinion as an external observer; I have no actual insight into what was going on.

Team Apple,

This is from someone outside the Apple ecosystem that management brought in and gave a lot of credence to.

I wanted to share a note of encouragement to say that everyone at NCMEC is SO PROUD of each of you and the incredible decisions you have made in the name of prioritizing child protection.

The recipients of this memo didn't make any of the decisions and those were foisted on them by management who in turn were heavily influenced by this person/organization. As to why management was so heavily influenced, I have no idea. This is an attempt to get buy-in from Apple employees I suspect, or at least to ease their concerns. "Don't worry, you are doing the right thing."

It’s been invigorating for our entire team to see (and play a small role in) what you unveiled today.

The team they are referring to are the ones that pushed for the implementation for child protection. The recipients did all the work because management told them to.

I know it’s been a long day and that many of you probably haven’t slept in 24 hours. We know that the days to come will be filled with the screeching voices of the minority.

This is the big quote. The author knew what this would do, and knows the tarnish the Apple brand is about to go through, but is trying to convince the audience that it's only a small group of people who will reject this and it will pass over. For the author, the ends justify any means because they are probably personally emotionally traumatized by child porn (rightfully so). Once this happens though, any rationality about consequence of action goes out the window. This is an attempt to get everyone concerned on the same level of ends-justify-the-means with the author. I don't know if the author believes this is just a temporary outrage or not. I suspect not. It doesn't really matter though the author got what they wanted, Apple brand be damned.

Our voices will be louder.

This obviously isn't the case. Not sure if the author means their organization or their organization + Apple. Either way, the counter resistance to this has been pretty minimal. They left Apple hang out to dry it seems.

Our commitment to lift up kids who have lived through the most unimaginable abuse and victimizations will be stronger.

During these long days and sleepless nights, I hope you take solace in knowing that because of you many thousands of sexually exploited victimized children will be rescued, and will get a chance at healing and the childhood they deserve.

This is the emotional sell, or "for the children." It's also a difficult bridge to reason across; comparing the possession of pictures and the manufacture of pictures as the same thing. Obviously the hash compare only finds existing manufactured pictures, so I don't see how it will protect children from any abuse that hasn't already occurred. Not only is this an emotional sell, it's a lie.

Thank you for finding a path forward for child protection while preserving privacy.

The final emotional pitch directed at people at Apple typically concerned with privacy. They aren't really protecting children and they also aren't preserving privacy. It's a boondoggle.

In closing, "for the children," is almost always a trap. It was used when I was a kid to mass incarcerate Americans that had drug problems, many of them the children they were protecting. It's typically done in an any-means-necessary heavy handed manner, as seen here. I don't condone child pornography in any way. I have never seen child pornography and hope to never see it. At the same time, what they are doing is the road to hell paved with good intentions seemingly by people who are so traumatized (based on their work) that they can't see the collateral damage they are doing.