Plenty of money for guns, but why does compassion appear to be in such short supply?

Why don't they have to appeal to the public to send in donations to buy bombs? After all, they have to beg for the money to provide food and shelter. BBC News 24 reported on Tuesday that the UN had asked for $$78m in emergency aid to ease the plight of 2,000,000 people in Afghanistan facing drought and starvation. That's a fraction of the money being poured into the country every month by Britain, the US, Canada, Australia etc. in the form of helicopter gunships and tanks and guns.