> The topic is about how people within these subsets of society begin to believe the norms of their subset are shared by society at large, or in other words - by people outside their subset.

Again, I think that's just a failure to frame the problem. Norms originate and develop organically within communities. If you have online communities that develop their own norms, and that community does not have a perfect 1-to-1 correspondence with other communities, such as your work or your local bar scene, then you're bound to stumble upon people who don't share them even though they are apart of other communities shared by you.

The same applies if you replace "online community" with "work", "bar scene", "school board", etc.

The only aspect that sounds remotely relevant is the online nature of said communities, but that's something that exist and is already known for decades.