I would agree with you here. I think he had to put significant efforts into it, and I think it would be both harder and more expensive to make it BIP110 compatible. So basically he's making two points: - A motivated state actor will always be able to put contiguous csam on bitcoin if they decide to do so. — you just won't fix that. - If we make it more expensive for spammers, we might end up in a situation where the spam becomes more damaging in order to get in anyway. However, he's also showing that counter-measures make spamming significantly more difficult. The problem being, once someone writes and standardize a work-around, it becomes easy again (just more expensive). Personally I would still favor easy/non-damaging counter-measures, but not as aggressive as BIP110 that will clearly come back to bite us.