If I click the link you provided, my browser takes me to Lenny.ml. There I am not logged in and my credentials from feddit.de are not working. So I cannot post there.
I think it only works if the link points to a community on another instance. Like !memes@lemmy.ml . Maybe this is the intended behavior.
The downside is, you can not visit an instance and view the local communities and their post and interact with them. This makes it a lot more attractive to join the instance where the communities are you want to frequent.
Edit: the link to the community does not work either for me. But I am kind of sure, that there are links that work as intended and make you just view the community from your own insurance…
Haben halt nicht den frühindistruellen Charm eines Kohlekraftwerks mit Tagebau daneben. Der Trick ist die Landschaft abzubaggern, damit man sie nicht verschandelt.