I disagree with how you frame my position. First the argument that criminals will always find a way around it is specifically why I think legislation should target VLOPs. Nobody can just build one of those, including criminals. If you want to firm up my position it's not that E2EE is the last battle against CSAM; rather it's that VLOPs proliferate CSAM in previously impossible ways, with a virality factor unachievable by older means. Criminals are of course free to return to Signal or whatever, but it won't give them the reach that Facebook gives them so it's still progress even if we didn't save every single child on the planet.
Moreover, I disagree (again) with your desire to pull my position into a theoretical debate about free speech absolutism. I just don't think two people on HN are going to get to the bottom of that one. But with a little nuance, which yes is messy, we can stop the proliferation of CSAM on VLOPs without constraining individual liberties. Just go do those liberties on anything except a VLOP.