Ethical Question

NY Times has a piece about residents of Maiduguri in Nigeria fighting against Boko Haram. It contains the following:

(The military and the vigilantes have each been accused of engaging in abuses in the name of ending terrorism: arbitrary arrests and beatings, summary executions, forced recruitment and the use of children in their ranks. Kalli denies that he or anyone in his group has ever been involved in any human rights abuses or that any members of his group are under 18. “We don’t kill anybody,” [my underlines]

Here's the question: Is it unethical or even a human rights abuse to enlist minors to defend themselves (and their place of residence against terrorists who would surely kill them?

Seems to me to be a false equivalency to compare a terrorist or so called "rebel" group who recruits children for the sole purpose of killing other people for personal gain (or amusement) with those who are recruited to protect their own lives and the lives of their fellow residents.