Because our current economic wealth is still substantially built on the riches robbed from other nations hundreds of years ago.
^^^This hence the large overseas aid budget!

Water under the bridge now what happened, happened end of story.
Problem is how do you deal with thousands of people trying to invade an island? Because that's what is happening, what approach do we take.
Do we stand at arms and shoot them?
Do we accept them with open arms?
Do we deport them to the nearest safe country they left?
Do we imprison them?
Do we set up a segregated island for them?
Its like what the hell can we do, that is ethical and manageable.

Answer is bugger all!
