The math is monumentally off. It fixates on 5 specific people having issiues, instead of: There exist some 5 loosely connected people that some HN-er heard about, and probably hasn't even met all of them in person, especially the ones that died.

The implied qualification of - there exists a HN-er so divide by 1e9 to get odds - is nowhere close to accounting for the additional degrees of freedom from the social graph.