The poster here seems to legitimately view it as an attack on some sort of perceived group identity, that it is somehow being imposed on them from the outside.

Of course, the people writing the codes of conduct are speaking for themselves, not the perceived group identity mentioned above, and the poster is attempting to speak on behalf of the group they see, probably without carefully apprehending the range of opinions that exist within the group.

I'd also consider the idea that much of the push back is disingenuous sophistry coming from people that enjoy going to conferences and hassling people.