That is a very dangerous way to think.

Cultural exchange is the key way to breaking down barriers, the more they learn about us and vis-versa the quicker things will change.

Isn't it true about any money that goes into North Korea?

They also receive substantial amounts of international aid and profit from endeavours like Kaesong. In the grand scheme of things, the petty revenue from tourism doesn't matter.

http://en.wikipedia.org/wiki/Kaesong_Industrial_Region