So would you label Ted Bundy a hardcore straight man? and Jeffrey Dahmer a hardcore gay man? Aileen Wuornos a hardcore bisexual woman?
Most people would find such descriptions offensive because they would suggest that to be a real straight guy, a real gay man, a real bisexual woman, you have to be a murderer and maybe much worse.
As you might guess, I find "hardcore pedophile" to be a poor description for anything, much less for someone who is the very opposite of a pedophile. Traditionally we have used "child molester" for someone who sexually assaults children.