There are gnocchi, gnocchetti (small gnocchi) that are pasta. What you know as gnocchi are properly called "gnocchi di patate" in italian, i.e. potato gnocchis
That's the answer, the gnocchi pastas imitate the shape of the potato gnocchi.
I also wouldn't really call potato gnocchi pastas, like if I invite people to eat and say I'm cooking pastas, nobody's expecting potato gnocchi. But I think in Italy they're in the same aisle as fresh pastas.
The thing is - and op's picture is correct - that italians actually differenciate between different shapes of pasta, for the simple reason that pasta shapes have functional reasons and different shapes correspond to different dishes.
Gnocchi are a varied family of Pasta in Italian cuisine. They are made of small lumps of dough most traditionally composed of a simple combination of wheat flour, egg, salt, and potato.