.world instance != Lemmy (lemny) The instance has some rules for content, and discussions around celebrating a murder are getting caught up in that.
There might be some overstepping of moderation in places, but it must be a bit of a minefield for the mods.
The best thing for you to get the experience you want from Lemmy is to engage in those discussions in an instance that suits your moderation preferences.
My first time in Spain I asked for café negro and was corrected to say con leche. Not in a 'that's racist' kind of way, but in a 'that is inaccurate, even though we understand' way.