I would say from a legal/moral/political philosophy point of view the difference is that the other implementations do the scanning on their servers, apple wants

I would say from a legal/moral/political philosophy point of view the difference is that the other implementations do the scanning on their servers, apple wants to do the scanning on my phone. Even if the outcome is the same this feels like a step too far. Even though in reality, I don't want them scanning my data regardless of where it lives. We have already been sliding down this slope, this is just one more step.