FB was the primary tool of RUS Intel Agencies' Active Measures attack against the US 2016 elections, against the Brexit vote, and against multiple EU elections.
They utilized Cambridge Analytica, Russian 'Internet Research Agency', and thousands of paid & unpaid trolls to micro-targeting voters for their specific psychologically tested anger trigger points, with billions of impressions of the same in the US alone,
FB at best ignored/minimized the entire episode, dismissing it for many months afterwards.
These attacks are in no small part responsible for the current administration, and at the very least for their inhumane anti-immigrant policies that have resulted in multiple deaths.
The administration, along with the Russians, is actively working to undermine every independent democratic and law enforcement institution that will not act as a support of the rule of them as an autocrat, vs the rule of law.
FB may well go down in history as the key element in the destruction of democracy itself.
That alone is a far larger consequence to the smoking epidemic (& I lost my grandfather to that).