"the company looked at the history of social media over the past decade and didn’t like what it saw… existing companies that are only model motivated by profit and just insane user growth, and are willing to tolerate and amplify really toxic content because it looks like engagement… "
I'm not sure if this is what that person meant, but, usually it's on the original development team to handle outreach and building the identity of the software - in Lemmy's case, they have a bit of a not-great reputation… Even if they had the reach, that reputation hurts.
Having Mozilla - or any top tier foss-friendly company - kinda take the reins a bit would probably be good.
I'm not sure if Mozilla is the one for that job, they have their own issues with community relations. I wish they didn't because the world needs Firefox.