When simply visiting the landing page for discuss.tchncs.de, the whole page is full of posts in communities that are hosted on lemmy.world and sh.itjust.works.
It’s a bit foolish because if someone wants to see posts for those communities, they would visit those nodes. If you visit discuss.tchncs.de the main timeline should show you a local timeline.
It would be sensible if someone is logged in to discuss.tchncs.de, in which case their settings would have effect. But it does not make sense to fill the page with foreign posts by non-local users to non-logged-in visitors. There is no user account and no community that traces to discuss.tchncs.de on the landing page.
Of course a visitor can click local, if they are familiar with Lemmy, but all is a shit default.