Nope. You're wrong, but you're in good company. You're disregarding the inter vs intra network differences. It's an important distinction.
Please don't think that because I'm from the USA I must be ignorant of German interpretations of law. I assume Gunter Kneips university paper (now a little long in the tooth but easy to read) is still fairly accurate regarding German law on the matter? I skimmed pages 4 and 5 to refresh my memory. You might do so as well.
I know Günter Knieps work, but I have to disagree here. Offering your own services without a limitation but heavily limiting others is privileging your own data. Technically you can maybe distinguish between internet and intranet, of course, but for the customers it's relevant what services and data they can access through their last mile, and here telekoms own network services, labeled as intranet, are still another internet services.
And this is why I say you are in good company. Your intuitive understanding makes sense, whereas the actual implementation often does not. If the laws were changed to make intuitive sense, though, I fear there could never be much real neutrality. Or, if there were, plans would all have to be pay-per-data-volume, which would benefit me, for example, but likely not many other users.
That or allow all telecom infrastructure worldwide to be state-controlled and maintained so that a tarriff approaching zero could be implemented with infrastructure costs recouped through taxes, but that too may be impossible.