Human interaction is really, really complicated.
No one understands it all the way.
Almost every rule has major exceptions. Anything stated in a clear way is going to be oversimplified in some way.
There aren’t rules so much as cultures and traditions that everyone finds their own way to work with.
The most anyone can really say most of the time is “this is sort of how it works a lot of the time” or, “this is probably going to be the case for almost everyone, if not absolutely everyone”. It’s hard to be honest about that, especially when you’re talking about an extremely important area of interaction like physical boundaries.
In addition, people will tell you all kinds of things they wish were true. One example is how people will teach kids “tell an adult” even in situations in which adults are unlikely to care about bullying. Or “tell them it hurts your feelings” because they want that to work.
Writing this blog, I understand more and more why people do things like that. It’s hard not to. But, it’s important. Everything is more complicated than I’m describing; even when I’m mostly right. (And sometimes I’m not.)
I’m saying things that I think are true, as well as I can describe them. But, don’t just believe me. And, particularly, if you think it’s more complicated than I think it is, don’t assume that I’m right and you’re wrong.
tl;dr Social skills are skills, and they’re complicated and to a large extent different for everyone. All descriptions, and especially all rules, are approximations are best.