I don't enjoy how the paper is blaming the writer and is not accounting for their obvious lack of facts checking because of their liking of "a good story". It's definitely a discussion worth from both sides, punching down on a pressured human being lacks good taste.
Although that guys lies did go to a extend that is also worth mentioning. When his collegue started questioning the truth of aome statements he faked a email correspondence and showed it as proof that he was right.
I agree tho, the Spiegel should still be able to catch the lies. This is on them.
There is a limit to fact-checking others can do. If it comes to bothering witnesses or travelling around the world then the limit is already reached . You can't really except them to do the same work multiple times with independant writers just to prevent something unlikely.
I guess they will now implement some solutions and find a middle way.