Wasn’t it KDE that had malware in its theme store not too long ago? Let that sink in for a bit. You changed around some icon themes and it executed arbitrary code.
And let’s not pretend that kde wouldn’t have an extension system if it could - but it’ll never have one because implanting one in that c++ spaghetti nightmare will never happen.
I think you meant to reply to this: https://news.ycombinator.com/item?id=47702680
But if not, I'm not criticizing GNOME in isolation here. It's just what I use and what I'm most familiar with. KDE has the same issues and it does have an extension system too. It's called KNewStuff.