When your research budgets are screwed down tight, you tend to focus on research projects that solve high profile issues.
Honestly, I think the CDC's ventures into non-contagious disease areas, some of which aren't even public health issues, is more a matter of justifying their existing budget and resource structure when the problem they're supposed to be dealing with (contagious disease, remember?) has been largely dealt with in the U.S., thanks to sanitation, vaccines, and antibiotics.
Smallpox, polio, measles, mumps, rubella? Pretty much any form of bacterial disease? Not really issues. Even HIV has been contained to the point where it's almost a self-inflicted wound caused by high risk behavior (unprotected sex and/or IV drugs). They're left with working on drug-resistant bacteria, planning for low probability, high impact things like the ChiCom coronavirus or Ebola, and beating anti-vaxers with cluebats.
IMHO, sending a bunch of CDC researchers to beat sense into Jenny McCarthy's head would be worth their whole budget, but that's just me.
We all know that .gov agencies aren't allowed to get any smaller, so they come up with other things to do, outside their original mandate, to justify themselves.