That sounds quite harsh. It generally fits with the idea that “Europe is a museum, the US is a factory”. You aren’t allowed to mess up the museum, you’re just supposed to appreciate it. However I can’t imagine that Germany doesn’t allow cabins, lake houses, weekend homes etc anywhere?
For cabins, the property has to be zoned as a recreational space. On agricultural land the structure you build has to be with an agricultural purpose and you can only apply for such a building permit when you are a registered farmer.
Pretty much everything is regulated in Germany which sucks at times, but also this is the reason why things work quite well even though we are densely populated.
.svg){kind=link}