Tbh I think there have always been mentally fucked up people like this (and far worse, frankly) but the internet introduced human psychology to the ability to spend many hours per week roleplaying anonymously online with other people, and somewhere along the line these people mentally lost the dividing line between their play pretend online experiences and the real world, it's like a new form of psychosis and like other forms of psychosis you can usually tell that they're very off in the mind and have the potential for aggressive breakdowns if you encounter them in real life, I've encountered 2 different people like this at different times and they're almost never just normal people who randomly one day reveal something of this nature, they start off with mentally unstable creeper vibes and by the time they make it known that they see themselves as sexualized hamsters or whatever nobody is shocked