Hi Alberto,
No I don't have any info on this. I did take a closer look though:
There it states data usage is only for (personal) educational purposes. Something that I would interpret as relevant for their own stuff, and ignore for the EU stuff (given the position of the EC itself on this).
It seems to me, this is a case of legacy: they started collecting this data in the 1970's and then it probably was the best way of maintaining the database in this external institution. It would be more obvious to have it at Eurostat, I agree.
It might be worth a try for you to e-mail the Open Data unit at the EC. Either Martha Nagy-Rothengass as head of unit, or Daniele Rizzi as the project officer for open data related projects. Writing Daniele, the angle could that you ask to see that data released as part of the new Commission Portal, and why it is now needed to register with a German company to get that EU data. That should trigger some formal response from them on how this is going to be added to their data portal, no?
best,
Ton