I have to agree with you. Though if you look carefully at the two penultimate pictures (the three windows and the bookshelves) you can see that a significant portion of the house is under ground level, so at least they made an effort. And the comment under the circular door photo mentioned also needing a standard door to conform to code, so perhaps a fully underground house would have some code issues with roofing or walls or some-such.

There is a separate article focusing more on the owner than the house in the news section of TCG, here.

By the way, welcome to the site!