It makes it clear that I have no common ground for this kind of discussion with that person.
That sort of trading genocide for one's own ego is Maoist and Stalinist, and it is really no different from their thought processes. Thankfully though stable political systems marginalize low-rank people like this. (Thus, be very afraid of revolutions).
Far from it, this is not even remotely a possibility. Mosquitoes are not threatening humanity with extinction in any conceivable way. As I stated elsewhere in this thread yesterday, if humanity were actually threatened by mosquitoes, I would support their eradication.
But apparently not about thousands or millions of individual humans dying.