Because you have to waste time reading it, and because they tend to force people to sugarcoat everything they say so that someone doesn't get "triggered" [1]. They also encourage SJWs (social justice warriors) to waste other people's time with various crap, for example the Node.js pronoun scandal [2].
I honestly can't see peoples objections to CoC. If as you say it doesn't actually change anything why do you object?