>In order to ensure the enemies are defeated the body itself makes the entire battle field cater to their advantages. Fevers, selectins, permeability etc all are auto responses to improve the wbcs shots at winning and being effective

That's the best explanation of why symptoms, such as fever, happen that I've ever read.

It's to disadvantage the invader and provides an advantage to the defense.

Sometimes the defense can cause more harm than good, but that's a different topic.