It is a legitimate defense strategy - and one that actually has valid points, at least for stuff like anime "CSAM". IMO, societies should focus more on preventing the
creation of real-life CSAM:
- teach children from a young age in an appropriate way about sex including what the names of genitalia are, so that in a court examination you don't have to argue about what "down there" means, and consent. Children can only report abuse if they have a third party telling them that what they experience is not normal.
- provide infrastructure for potential pedophiles to get help. In Germany, we have the campaign "Kein Täter werden" since 2005 and oh boy, that was a mess to get started due to the (justified) public stigma against pedophiles, but it ended up preventing thousands of crimes [1].
- for the US: ban home-schooling and force all children through the public or accredited private school system so that (religious) cults can't go and indoctrinate young children into being breeding mares or abuse them with virtual impunity
- provide teachers with enough resources (time and training) that they can spot signs of abuse (and not just sexual, but also physical and emotional!) early on
- provide get-help infrastructure nationwide: anonymous phone help lines, "safe houses" for people of all genders and ages attempting to flee domestic violence and sexual abuse, easy and equitable access to restraining orders, provide CPS with enough financial and staff resources to do their job properly...
Unfortunately, the first three measures are highly politically charged and so won't pass, and the last one is expensive so it won't pass either, and as a result children all over the country end up being abused with no way of getting help or worse, not even knowing that they could get help.
[1] https://de.wikipedia.org/wiki/Kein_T%C3%A4ter_werden#Ergebni...