You really think Nick Szabo, Luke, and Mechanic don’t know there are chunks of data in the blockchain that when put together and run through a special software CSAM can become consumed?
Maybe just maybe their point is that with the changes to OP_RETURN, people will be able to have contiguous blobs of CSAM in a single block that can be easily be consumed. And that this can rightfully bring scrutiny from governments making it a liability to run a node and be sovereign. And even if governments turn a blind eye, a lot of people will stop running full archival nodes because it’s morally wrong to host, distribute, and enable CSAM.