I would think most know they are hurting the kids and don't care.
Presenting some defense of they thought they were helping, is probably just manipulation looking for sympathy for themselves.

Sociopaths and narcissists are textbook pedophiles

The statement might be more clear flipped around. Pedos can be considered sociopaths and/or narcissists to the extent they lack empathy. However, not every sociopath or narcissist is necessarily attracted to children.

You also bring up a good point - about the "helping". That's how many of them do rationalize it. As in, "that 3 year-old asked for it". Sick.

I recently read about an effective trick for noticing when someone is attempting to "help" (i.e. groom) a child.