I heard there is a theory from therapists that being able to create that content can help quell urges, and so we should allow it if it protects real kids, vile as it is. However others argue it could cause it cause more to cause harm.
Either way, the decision is well above my ability to decide, and while I would hope actual professionals would have a say, unfortunately it's going to be a political thing. Pandoras box is wide open though.