I can see how this truth fits in to this debate in multiple ways:
1) CSAM is probably already in the chain using the inscriptions method
2) CSAM is in the chain from years past
3) op return limits aren’t meaningful limits for spammers because inscriptions method get then 4x more space at ¼ the cost for spam
4) inscription technique is a cost to use in and of itself: it requires more brain power of the spammer to use inscriptions to spam over op return
5) Code for returning CSAM from bitcoin block is longer when stored in inscription format as opposed to op return or older storage methods , but never the less any code for reconstructing CSAM from blockchain can be a one liner on the command line.