No, it's just standard web developer laziness. They haven't made it IE only, they just broke the less popular browser, and likely anything else that is not chrome/blink, because chrome/blink is the new IE: its bugs define "correct behavior" it shipping something means "it's standard", no different from the "IE is the internet" era (and just like chrome there was a long period where IE was the best browser, before devs started targeting it alone).