In which episode(s) did he talk about it? I checked 2 or 3 episodes around that time and it did not come up. We are talking about the Waveform podcast, right?
Besides that, I'm sure his reach on Social Media & Youtube is quite a bit larger than on his podcast. And I guess, the reason he had those comments under his videos was, because those people don't listen to his podcast either.
FWIW, he does talk about CSAM and is definitely aware of its pitfalls on his podcast, so it's not like he's blindly banging the drums.