Episode 5-23, I Borg

I remember when First Contact came out and while everyone loved the movie, a lot of people complained about their being a Borg queen, but I always considered her to be a result of this episode. Individually would not destroy the Borg, they would adapt it somehow while still remaining mostly Borg. The really interesting aspect of this episode is the ethical concern of using a living being as a means to kill its entire species. Is killing every mosquito on earth ethical because they spread malaria? This episode side steps giving an answer by allowing Hugh to rejoin the Borg in hope that individuality will infect them, but the question remains: is killing an entire species ethical?