In the context of this barbaric primitive society, it was actually very forward-thinking of them to issue a warning, and then only do the killings after the warning was ignored, and to kill the man too. Warnings are rarely issued, especially in cases where the relationship has gone as far as sex. Plenty of women/girls have been killed just for talking to a man/boy, and usually the man/boy isn't killed. And then there was the guy who killed his 2 or 3 young daughters last year, because he was afraid they MIGHT someday dishonor his family.
Hope these guys are enjoying their "honor", while shackled together at the wrist in a jail in Donga Bonga, awaiting trial in front of a judge who's likely to be unsympathetic.