It's not a zero sum game. Expressing compassion for refugees doesn't mean that you're indifferent to suffering at home - some of us have already taken in children from the social care system in the UK
Actually, according to this report in 2012, only about 2.27% of the country is built on. It may have gone up a bit in the last few years ... but not by very much. But you rightly point out that the real problem we have in this country is the number of NIMBYs - we could easily cope with a couple...