Technically speaking, it was not Lufthansa but Lufthansa CityLine. And the article does not quote a Lufthansa spokesman (why would Lufthansa speak for a separate entity?). The correct translation is along the lines of "At Lufthansa, the word is ...".
BRE, it was Lufthansa:
Bei der Lufthansa heißt es, dass die Kennzeichnung des Flughafens irreführend gewesen sei. «Nach unserer Information war die Bahn nicht wie im Weltluftverkehr üblich durch Kreuze gekennzeichnet», so ein Sprecher zu aeroTELEGRAPH. Zudem sei sie voll beleuchtet gewesen, sodass die Crew den Eindruck haben musste, die Bahn sei nutzbar.
It was Lufthansa spokesman, quoted here.
"...the crew must have had an impression (Eindruck), the runway were in use."
I would prefer they would fly according to procedures and knowledge, not "impressions".
They shouldn't start blaming others for their own clear cock-up.
Let's wait for the preliminary report of the Polish AAIB (PKBWL) to have all the relevant facts.
Regrading Lufthansa and Lufthansa CityLine, I was flying few weeks ago to MUC with LH, and back with CityLine.
There was clear difference (by the same ticket price) in quality of on board service between the two. It could be assumed there might be the same difference in other aspects of procedures between the two operators.