I think it is really important that children are aware of how their lives are different to others and how we in Western society are lucky to live the lives we do.
As a teacher, I often discussed news articles with my year four pupils, but I generally used First News, which is a newspaper for children. I have no problem with discussing news events with children because it is important for them to have an awareness of the world around them.
I also wouldn't have a problem letting children of mine watch the news, lunchtime news, the six o clock news. There are generally censored images. I think a child hearing that soldiers are fighting in Afghanistan with footage of men in uniform is a lot different than being asked to imagine a child having someone pour petrol on them and then being set on fire.
As a teacher, I would probably have substituted the line. In my classroom I would have no problem teaching children that there are others out there that are being hurt by people they trust and that we can perhaps help them. To me, though, there is a world of difference between saying
"We are very lucky here because there are people that we trust to look after us and they do it well. Other children in other situations aren't so lucky - they are made to work all day in xyz conditions and sometimes they are hurt and not looked after properly."
and
"There are children out there who have petrol poured on them and are set alight. There are children who have their bones broken on purpose. There are children who are so malnourished that they will die a slow, miserable death. There are children who are being raped and horrifically mutilated, can you imagine it? Imagine the blood and gore and pain."
There is a difference between specific images and general facts, and for me the fire line is a specific image that is not necessary.