I'm not sure how to classify it adequately. It may be that classification is inevitably oversimplifying. But, I do think that it's a close relative of conservat

I'm not sure how to classify it adequately. It may be that classification is inevitably oversimplifying. But, I do think that it's a close relative of conservatism that's found in almost every culture and can often get very extreme. Strict codes of conduct, dress, speech and such are a consequence of people instinctively creating and policing conformity. That can be thinking and voicing a dissident opinion about religion or politics, dressing outlandishly, speaking improperly or any other element of culture that's cohesive. It isn't a coincidence that in 18th century Japan and 18th century Morocco, people wore different hats. That conformity in hats happened as people themselves conformed to local hat culture and pressured those around them to conform. I think you're right to call it juvenile. Juveniles seem especially vigilant about conforming and policing conformity. A 14 year old is more likely to berate a nonconforming classmate than a 40 year old. Being online and anonymous tears down some of the barriers to both taking offence and offering it. But, I think that the instinct to find a core identity and violently defending it is, unfortunately, innate.