Couldn't it also be seen as a forking point of accepting (integrating) or rejecting the new element? With maintained or increased fitness the host organism surv

Couldn't it also be seen as a forking point of accepting (integrating) or rejecting the new element? With maintained or increased fitness the host organism survives. With rejection, the new element becomes by definition a pathogen. From an objective point of view, organisms that incorporate pathogens and survive become more aligned with the surrounding environment, adapted. Evolution is brutal, but is it irrational ?