More than protective, it wants to expand, and that's a problem.
But going back to the protective aspect of it.
When you started to give up your humanity to it, it will never let his host down, despite our efforts to make it lose it's grip.
At this point, it's too late to turn around. Cure is needed indeed, but alot deserted us dor the benefits the pathogen gives (that's maybe where the strength rely).
Honestly, those types of pathogen are a nightmare that would make me cry and lose my shit, but I don't feel like saying goodbye... yet.
Cause if it ever happens to run around without us making the test needed to assure it's safe, it'll hurt alot of people.