The Others have not (as yet) hurt anyone really. They just take ppl against their will.
The only person that I did see killed by a "other" is nathan, by that other guy who Ana Lucia later killed. She asked him why he killed Nathan and he said because hes a bad person.
How do the others know everyones names, who they are etc.
And who are they to judge who is a bad person? or a good person?