if you’re genuinely curious: my bet is to avoid lawsuits. mind that people who use the word pedophile colloquially usually mean people who prey on children.
in reality, pedophilia is not a legal term and not a part of the crimes or charges. it’s a psychiatric disorder and in itself not the crime. laws are not concerned with the disorder so long as the person does not act on it.
on the legal side, crimes like statutory rape, child sexual abuse, or whatever it may be, are independent of the disorder and i would imagine a lot of people who engage in it might not have it; as sexual abuse is more often than not about power, not attraction.
so i imagine shit stain perpetrators like this can technically say they’re not pedophiles as they aren’t legally found to be so and sue for defamation. so media sticks to the legal terms.
that being said, even if they don’t use the word, they should mention that the victim was a 12 year old. so instead of pedophile rapist, it can say rapist of 12 year old. afaik that’s legally and technically true and shouldn’t be a legal liability.
disclaimer that these are opinions of a layman, and I’m not a lawyer.