

You talk as though closed-source developers reviewed all the upstream code. The exact same problem exists with closed-source, except there isn’t even the possibility of reviewing all the code if you want to. At worst, the lack of review in FOSS projects is on par with closed-source projects. At best, it’s a much smaller problem .
Censorship is bad, but Facebook and X’s entire business models revolve around spreading content that is at once false and inflammatory, either just to create engagement or for more malicious purposes, and they reach a huge portion of the population directly, including children, teenagers, the mentally ill and other vulnerable populations. This requires a new understanding of accountability for spreading information.
I wouldn’t agree that it makes sense to hold a Mastodon instance responsible for what its users post, because they don’t have a financial incentive or the ability to promote misinformation at a massive scale. Twitter does. As Aristotle said, we must treat equals equally, and treat the unequal unequally according to the form and extent of their inequality.