Another parent's different approach raises the possibility that you've made a mistake with your child. We simply can't tolerate that because we fear that any mistake no matter how minor could have devastating consequences. So we proclaim the superiority of our own choices. We've lost sight of the fact that people have preferences.
You can't control the paparazzi. But if you go to Coachella you're going to get photographed. Whereas if you're at home walking down the street you probably won't. It's something I've learnt to navigate my way around but I try to keep my private life private.