Firefox went to an evergreen browser model and keeps an ESR around for people that don't want to upgrade. But that's at version 45 at the moment.
Firefox 33 is a three year old point release intended for eight weeks of operation, so things being broken shouldn't be a surprise. So sites have the choice of feature-sniffing and keeping an updated list of all the rendering bugs in all browsers going back ... what, a decade?; or kicking out people using old non-ESR browsers. They could be more gentle about it, but the choice is fairly obvious.
Firefox 33 was an official release. Things being broken should be a surprise in an HTML5 compliant browser.
If sites use bleeding edge features with no programmed fallback or error handling apart from "miserable failure", they have a responsibility to at least inform users of their limited browser support rather than pretending to be a website on the internet - which by its nature should be accessible to an official release browser from 2014 without failing miserably.
Firefox 33 is a three year old point release intended for eight weeks of operation, so things being broken shouldn't be a surprise. So sites have the choice of feature-sniffing and keeping an updated list of all the rendering bugs in all browsers going back ... what, a decade?; or kicking out people using old non-ESR browsers. They could be more gentle about it, but the choice is fairly obvious.