I have a theory, more of a headcannon really, that coughing and sneezing actually evolved (in part) to deliberately spread infectious agents, as opposed to less

I have a theory, more of a headcannon really, that coughing and sneezing actually evolved (in part) to deliberately spread infectious agents, as opposed to less-atomizing means of clearing mucus. Airborn viruses are typically non-lethal (otherwise it would wipe out the species readily), and it would have the effect of spreading these and creating survival pressure which culls the weak, freeing up resources and enhancing selection. The anti-outsider effects would also be a perk.