Mosquitoes are the only natural predators of humans. If you mess with the delicate ecosystem, humans will procreate uninhibited and exhaust their resources, leading to a far worse fate. It's kinder to just leave the mosquitoes be, and let nature run its course.

The males don't bite, but the females need that sweet protein from blood to grow the next generation. Exterminating all the females (the biting ones) would end the whole population.