In the quote above, Gandalf only advises that one should not strike without need. In the cases of both mosquitoes and orcs, it's not at all clear that xenocide

In the quote above, Gandalf only advises that one should not strike without need. In the cases of both mosquitoes and orcs, it's not at all clear that xenocide is requisite to ensure the safety of humans or the many dwellers of Middle Earth.