Implying that any form of socialism ("leftism") is only the struggle and the interest of "the proletariat" is like implying that feminism is only for women.
Everyone benefits from feminism, just like everyone benefits from socialism - because it makes the world less toxic!
And I'm pretty sure money is just as toxic as masculinity, and probably in many of the same ways.
Sunbeam City is a Libertarian Socialist solarpunk instance. It is ran democratically by a cooperative of like-minded individuals.