As a dev, I understand push back a bit after working on a long project in the "I really can't deal with more of this" sense (like if you just put in a 12 hour day to get a project done and then the next day are told you need more stuff. But beyond that I don't see why people fight so hard to say things are okay. To me WCAG is effectively saying "you should make your interface work for everyone, here are the things you need to do to ensure everyone receives a quality experience"