Wikimedia Germany is also legally seoparate from the Wikimedia Foundation, and still everyone considers them the official German offshoot.
They represent OSM in Germany, they think it's in OSM's best interest to draw attention to this issue, they do so on their own website, leaving all tile servers etc alone. I can see being momentarily annoyed at it, I can see disagreeing with them (politically or if that's a useful protest form), but I don't see anything that would count as a gross violation of trust or something that's out of scope for a local chapter to do.
FTFY
[0] https://wiki.openstreetmap.org/wiki/They_are_using_OpenStree...
[1]https://wiki.openstreetmap.org/wiki/List_of_OSM-based_servic...
The only basemap which has blocked tiles is OSM deutscher Stil, you can easily switch to the other three. Would argue that is very usable with very little effort on the user's part.
The FAQ I quote-translated could have mentioned that, instead of saying "there is no way".
After all, isn't the purpose of a protest to be inconvenient and draw attention?
Reload blocks different tiles.
"How can I remove the black error tiles?" – "You can't, at all. But in a few days we're going to restore functionality."
And they mean it. They haven't even made it so that a reload blacks out other tiles. No, they really want to make it utterly unusable, even with effort on the user's part.
So now the German OSM holds pretty much the same place in my heart as the German Wikimedia club.
The OSM Foundation needs to react harshly here. To think that I used StreetComplete just yesterday. That will certainly stop.