None of which has anything to do with having a double standard. If you ran your project with backwards compatibility as a core value and promise to your users then don't be surprised if they get upset when you break that promise.

It can be good to recognize that back-compat has become detrimental. When that happens, you need to communicate the reasons why you have decided to break it and communicate that the projects values have changed going forward. It doesn't sound like either of those things have happened here.