'Actively censor ... a troubling issue'? You make it sound like a police state.
Firefox has been losing market share for some time now, and this trend will only continue as long as Firefox's performance problems go unaddressed
Firefox's problem is shedding it's past reputation. It really isn't that slow anymore - it depends on what you're doing in the chrome vs firefox wars. I work with a bunch of chromeheads, and they all spurn ff because of that past reputation.
In actuality, they have as many problems with chrome as they do with firefox - I'm constantly saying "[bug] not evident on firefox" and they express puzzlement that The Awesomeness That Is Chrome actually has a problem other browsers don't. Not to mention that a lot of the bugs I do run into on FF are because of their 'designed-on-chrome-for-chrome' default mindset. The bugs do get sorted out, but the perception that FF is so much worse than chrome isn't reflective of the truth of the matter. They're pretty similar these days, swings and roundabouts.