Just to make my position clear, I am all for protecting children against child trafficking and sexual abuse. I just think it could be better done without resorting to Orwellian implementations of technology. So yes to protecting children but not at the cost of putting an entire continent under continuous monitoring.
The argument "think of the children" is being used to shoehorn these kinds of technologies onto the tech industry and social media. Because who in his right mind would be against protecting children? But as gustl points out, a lot of people are up in arms because of this and with good reason.
I am still curious to learn how GrapheneOS could protect people against these kinds of technologies. I doubt that they'd implement code like this.