Earlier quoted context omitted.
Every forum has an algorithm (including this one, which sorts by upvotes and hides dead content unless the user asks for it).
Hacker News in absolutely no way shape or form has an algorithmic system on the same level Facebook has, it is manifestly a bad analogy
A possible question of interest, were this lawsuit to find Facebook guilty, is "If someone somehow gamed HN's algorithm (which is relatively simple, so would in practice be pretty easy to game) to encourage a genocide, should HN be liable?" How complicated the algorithm is likely does not enter into the reasoning for culpability.