It's related to an overall value on "Purity" as a moral virtue.
I think what happens is that people like the author are very influenced by shame and therefore project the intent to shame on situations when they FEEL shame.
If I do something and someone tells me not to, I don't feel "shame", regardless of whether I agree with the direction or not.
That's not the case with some people.
I believe it's also associated with narcissism. If you are powerfully negatively impacted by shame you will do everything possible not to feel it including intense denial gaslighting and narcissism.