I take issue with them because a Codes of Conduct doesn't make a space safe. And also because if we need a written list of what behaviour is tolerated, we have a much greater problem than a code of conduct will solve.
I've seen people write about the former; I haven't about the latter. I find a CoC offputting because it equates me with the lowest of the low. It says I can't be trusted to behave like a decent human being and need to be told what's right and what's wrong, like being back at school.
I also see it as darker than "assumes that everyone else thinks just like them". Some - not all - are about controlling the world into the form the CoC proponent(s) want it to be. The CoC goes beyond its words and into society.
Neither do I support the Meritocracy thing, as I've had it used on me too many times by people who are super-smart and see that as a reason to be jerks.