“Motte”: unobjectionable position no one would disagree with.

“Bailey”: more extreme position; the one you actually believe and that people take issue with. Must not directly logically follow from the motte per se.

Motte & Bailey (informal) fallacy: Jumping between the motte and the bailey for rhetorical effect, as convenient.

In this case, the motte is “codes of conduct are just like the HN guidelines, they’re everywhere and no one objects”. The bailey is the actual CoCs in question, and the culture of pushing projects, conferences, etc. to adopt them, which tends to be rooted in “liberal identity politics” or whatever you want to call it.

When people criticize the latter (the bailey), advocates retreat to the former (the motte) - they’re just normal guidelines like “be nice”, basic manners, who would object to that? - and then when the argument is over continue pushing for the latter.