The other argument could be that it increases the chances of someone moving on from the consumption state to the abuse state.
But having to train models on real materials is a major moral issue.
This is actually my opinion but I have no hard data on this. Is it feasible to apply the same logic as with video games where realistic killing is depicted and the argument is that this doesn't make people killers in real life?
South Korea has jailed a man for using AI to create sexual images of children
The issue is that hash-based scanning will be rendered irrelevant by AI-generated images because there could be an unlimited number of them, and they could be produced by general-purpose image generating software that isn't itself illegal.