CSAM is some pretty bad stuff but case numbers are often wildly misleading. A big share (in my country some 40+ %) are minors and teens sharing images of themselves or receiving images from their bf/gf.[1] Another chunk is parents or teachers trying to report it and invariably finding themselves in possession of CSAM (e.g. teacher sees pupil has image of a naked 13yo on their phone, takes phone from them => teacher intentionally gained possession of CSAM => will be a felon shortly). Traditionally such cases would be dropped, but around here it was recently updooted to felony status, which means cases cannot be dropped.

[1] Jurisdictions vary wildly in how they prosecute this but many seem to have funny age combinations where e.g. a 13yo sending an explicit image to a 14yo means the 13yo can't be charged for producing CSAM but the 14yo committed a felony by possessing it. Some jurisdictions have charged people for sex trafficking themselves in these situations. It's all pretty insane if you ask me.

Edit: Worth pointing out that the organizations that push hardest for legislation like this (mostly christian fundamentalists) also care the least about these side-effects, because sex before marriage is a sin and ought to be illegal anyway. A conspiracy theorist would hypothesize that these side-effects are actually the intended main effect for those groups.