I didn't read it as how to take down an outsider, because why would an outsider care how "they do things there"? If someone has a club where they only open door

I didn't read it as how to take down an outsider, because why would an outsider care how "they do things there"? If someone has a club where they only open doors with their left hand, it isn't particularly interesting to me as an outsider who isn't subject to the same rules. It seems more about educating a newbie to the group, or someone in-group who broke some social rule, in a manner that accepts no rebuttals. The "we" in that sense seems inclusive of the person being chastised too. If a parent says to their child "We don't throw balls in the house", they aren't saying their child isn't part of the family. Having said that, I don't like this advice because it is condescending(which is why it was so easy to find an example of about a parent-child relationship).