Yeah, a lot of it is elitist. In other parts of this thread people are complaining about Vimperator being broken by the switch to WebExtensions.
The switch to WebExtensions allowed all the excellent performance improvements we have been seeing in Firefox over the last year. So it improved the performance for everyone, and broke a feature that a small minority used. That minority is a highly specialized, highly trained, bunch.
If you think that features that benefit a small elite group of users should trump improvements for all, then I think that is an elitist attitude.
Also, here there is absolutely no talk about changing extension APIs. So I don't see why extensions that work now shouldn't continue working in FF Preview once Extension support is added. The situation is pretty unlike the WebExtension situation.
So yeah, hold their feet to the fire to make sure that things don't regress without need. But also look at what they are trying to do with merging the FF Focus stuff in, and getting a built-in adblocker. They are doubling down on privacy for all. This should be commended.