I'd probably like to see if that gets reported from official sources rather than a Twitter feed myself before assuming its correct, a quick flick and I can only see a very small number of iffy looking account reporting it, not a single reputable media source from any nation.
I suspect there are a large number of potential suspects being watched in Germany, probably a magnitude greater than what were dealing with in the UK, at some point you can't keep tabs on all of them, and this guy appears on the face of it to have been a lower threat given it seems he wasn't seen as a typical Islamic/Muslim extremist.