Your assessment about copyright laws in Germany (EU) being similar or same as USA while in functionality might be true, they are completely different laws. Otherwise, Europe would be seeing Razor Crest LEGO sets just like we are in the USA.
I can tell you that the images I saw on the Bluebrixx website would not fly in the USA. And even if Bluebrixx could win the court case (unlikely in USA), USA corporations would make sure to destroy Bluebrixx in litigation and bankrupt them before allowing them to use anything that resembles their property without proper licensing. (Keep in mind, we're not talking about just one corporation but multiple).
BTW, you're assumption that because a company has been doing something therefore they are legit, is presumptuous. A toy company can avoid attention until they can't. Example: Modbrix. How many of us had ever heard of this company before someone there copyrighted the name "Razor Crest" or better put, Disney / Lucasfilm tried to do the right thing and found someone else had beat them to it? I believe this is how Bluebrixx has been avoiding attention, they aren't using the names, just images. But in some cases (new sets) they are using the name, so how long until they are in the news?
Modbrix had copyrighted the name and image of the Razor Crest 30 days before Disney filed paperwork to do the same. Now, I'm reading that Modbrix produced the brick set without the original designer's permission, nor was the original designer receiving any compensation from the sale of said brick set. They apparently rectified this after the fact, but that should never have happened. This is the same kind of junk the Chinese knock-off brick companies pull and not just with LEGO, but with rebrickable and LEGO ideas designers as well. This is not cool on multiple levels.
Update: As of last Friday, Lucasfilm now officially owns the "Razor Crest" name in Europe and Modbrix is no longer selling their Razor Crest brick set. https://www.stonewars.de/news/razor-crest-wortmarke-deutschland/