no conspiracy, just plain old sloppiness and nobody stepping up and assuming responsibility - very typical for Berlin state politics. The airport is state-owned, and all supervisory committee staff is - politicians.
The airport was built with blatant disregard to the fire safety provisions specified in the building permit (OK, such things happened in the past with public infrastructure projects), and authorities refused to approve this, grant an exception and let it open anyway (this is new - but to be expected after the '96 DUS fire with two terminals destroyed and 17 killed, which led to toughened regulations. Overseeing authority just would not budge). They have to re-do the whole fire prevention concept, which is not easy with everything already built and in place.

Here's some coverage in English: http://www.thelocal.de/national/20130107-47175.html

I don't care much - I like TXL. OK, it's overcrowded and getting pretty seedy as nothing is invested in it at all any more, but it's still so much closer to the city center. Actually, I still lament the closure of THF - out of the plane and into the subway in ten, at my destination in twenty minutes...