Which mental illness or illnesses are you claiming that it is symptomatic of?

Pedophilia is considered a mental illness under DSM-5 and ICD-11. Although admittedly someone can view child pornography without being a pedophile.

The DSM is a bit vague and outdated. Until fairly recently, a number of conditions which were similar but different were lumped in as one thing in research and the media.

Some people have an OCD which makes them obsess over children but they're not interested in them per say.

Some people insert themselves as children. This could happen due to abuse and neglect in their childhood or other factors. Some people are into certain aesthetics and media like cartoons and are not so interested in actual children.

There are two proper types. Exclusive and non-exclusive.

One is the exclusive who are alien in thinking. Instead of thinking of adults as romantic or sexual partners, they're wired to think of children. Without adequate socialization, they may even think of it as harmless to do. Education is vital.

They will be very lonely and depressed throughout their lives as it is impossible for anyone to allow them to do such a thing. I can't imagine someone going their entire life without ever fantasizing or looking at some sort of porn. Even as an escape. It isn't healthy not to do so either. It would only serve to make them more frustrated and to adopt an antagonistic relationship with society.

The non-exclusive aren't just attracted to children.