I'm probably quite biased being German myself, but I feel like that things like privacy and security tend to be more important to Germans than to other folks. And I don't speak just about the tech bubble, it shows everywhere.

To give a random example, when a license plate has been blurred in a photo posted anywhere, chances are high it's been posted by a German. Despite the fact that there is no license plate lookup (like carfax for US, finnik.nl for Netherlands, car.info for Sweden etc) so a license plate wouldn't even reveal anything to anyone, yet we treat it like a secret on instinct. If you ask such a German why he blurred it, he probably won't have a reasonable response, he just does it because he feels like it.
(Edit: Just look through the used cars here, most if not all will have their plates censored given they have plates on them lol)

Getting back to topic, this might not be the only explanation, but I'm pretty sure it's a noticable factor why Germans are especially present on platforms like this, i.e. platforms that tend to respect the user's privacy more than the big tech corporations.