More anecdote too but worth noting that of the friends of mine from childhood and high school who did later turn into really bad apples, all but one had come from broken or dysfunctional homes and social landscapes. The only exception to that was one friend from a good family who later ended up serving over a decade for kidnapping and armed robbery. He had made friends with a pretty rough crowd well before that. In all cases, seeing some porn before they were adults or seeing other nasty online content had only the most absurdly dubious connection to anything about their future conduct.

If anything, I see rules for content control in minors as a very convenient step by government to kill two birds with one stone: On the one hand, implement more social control, surveillance and normalization of restricting access to unpredictable media (dangerous that for government bureaucrats who want to control narratives). On the other hand, offset blame for systemic problems in a society on "dangerous online content" instead of government's own potential failures in managing a legal system, mental health services or economic administration and etc.