Why isn't there a Cambodia sub-category under the Travel category?

Probably because those countries have very few visitors, perhaps if there were more interest, there would be a sub-category. I am planning a trip through those countries to China and would also appreciate more travel info, but it's a matter of demand rather then discrimination. Those countries aren't commonly known as tourist destinations. Laos is actually considered as the most bombed country in the world and has been struggling to build its image as a tourist destination.

-from Malaysia

I am pretty sure there is not a category on clowns with hip replacement problems or seagulls with eyepieces but I doubt that means they are discriminating against them.