[Hey, I thought I was the token epidemiologist! ;) ]

I largely agree with Anders' comment (leave Pearl be for now; it's a difficult book), but there are some interesting non-causal mathy epidemiology topics that might suit your needs.

Concretely: study networks. Specifically, pick up the book Networks, Crowds, and Markets: Reasoning about a Highly Connected World (or download the free pdf, or take the free MOOC).

It presents a smooth slope of increasing mathematical sophistication (assuming only basic high school math at the outset), and is endlessly interesting as it gently builds and extends concepts. It eventually touches many of the topics you've indicated interest in (game theory, voting, epidemic dynamics, etc), giving you some powerful mathematical tools to reason with. Advanced sections are clearly marked as such, and can be passed over without losing coherence.

And hey, if the math in the advanced sections frustrates your understanding... that's basically what you've said you want!