I think that quite a few engineers are too focused on the technical aspects of it, and specifically on all those "barriers to misuse" that Apple claims to have in place. But it'll be much easier to remove the barriers once the system as a whole is in place.
The reason we're focused on the state of it now is that we can switch at any time - especially if those barriers are shown to be ineffective or are removed at some point.
That just ties back into "be afraid of what it could become", and isn't dependent on Apple making this system - Congress could have forced PhotoDNA to be shipped with phones since the inception of PhotoDNA in 2011[0].
https://news.ycombinator.com/item?id=28239506
I think that quite a few engineers are too focused on the technical aspects of it, and specifically on all those "barriers to misuse" that Apple claims to have in place. But it'll be much easier to remove the barriers once the system as a whole is in place.