Thanks very much for posting that interview. I thought it was good (and honestly impressed that it was quite respectful communication all the way around, as opposed to so often what I see as "debates" on TV), but I admit I got super frustrated to the point I could only watch half of it because nobody wanted to clearly admit to the other side's quite obvious point.
I think the Signal president was making great points, but she definitely was avoiding a clear response when asked about "If people are sharing CSAM on your platform, you wouldn't know about it, correct?" and "If people are violating your ToS, how would you enforce that?"
Obviously, the clearest direct answer is "Correct, we would have no way of knowing what content is being shared on our service." She complained about "circling the drain on the issue", but the reason they were circling is that she didn't want to say that sentence. And I get it, in today's day and age news organizations love to take a quote out of context and make it the headline ("Signal president admits they can't enforce their ToS against illegal material!!")
But debates like this are a waste of time when both sides refuse to admit the obvious implications of the other side's points:
1. The Signal president was making very clear there is no "halfway" encryption, that it either works or it doesn't, and the bill required a back door. The government minister was pretending and talking loads of BS about what "options the regulator has", even while conceding the point that you can't have a backdoor that only "the good guys" can use. What an exercise in cognitive dissonance.
2. The Signal president obviously knew "Yes, people can share CSAM on our service and we can't directly know about that content", but (and I think for good reasons) didn't want to say that obvious point out loud.
This debate would make more sense if both sides would just admit there is no "halfway compromise" to this issue. I agree with another comment that Apple really fucked up by thinking their "fingerprinting" approach was technically viable, and that somewhat poisoned the well in this debate.