A cold sore is still a negative consequence for the patient.  I'd be hesitant to call it a disease, but that's very subjective. 

My "deterministic" comment refers to claims of genotype determining phenotype. (Although, all scientific theories are ideally deterministic, in that A demonstrably and uniquely determines B. In reality it's rarely so simple and we settle for "A influences B" rather than "A causes B").  

The model that your genes are solely responsible for your phenotype is quite outdated, and often flat out wrong.  Intersex and gender ambiguities very much exist, there is often a discord between mental, physical, and genetic features. And, no, the redwood tree is not a valid comparison. The "male" state is derived from and closely related to "female", "tree" is neither. 

The reality is, that nobody really knows fully how one leads to the other, so the binary model is somewhat unsupported. Actual empirical observation seems to support that it's a spectrum.