"...people simply enjoy the adrenaline fix that goes with the state of "Being Afraid Of Something.""

While you're right, it's akin to enjoying your heart beating. Assessing threats is a primal function living organisms must undertake. We evolved in a world where the primary threats were other groups, and lions, tigers, and bears, at least that we were able to counter. While disease was likely the greater threat, there was simply nothing we could personally do about it other than avoid contagion. Rotting corpses stink, and that's about the best we can do there.

However, enemy groups require subtle consideration to be secure against. In 1911 there were a thousand princes in Russia, and in 1921 there were none. The fatality rate for Russian princes in that decade was 100%, and humanity was unable to secure itself from that threat vector at all.

It is not surprising that we err on the side of fear.

Thanks!