"Hustle" is a word used often on a sports field to basically mean "work hard." In business environments, this is what it almost always means - someone who goes out and works hard to get the job done.
with regards to [0] You're using definition 1. the writer is referring to definition 4
although it does seem like the writer is ascribing uses of definition 3 instead to definition 4.
I think hustle is really doing whatever you can to get from A to B, and in the context of a startup, "hustlers" use their bullshit - whether that's pizazz and shiny things and empty or extreme promises - to move from objective to objective in pursuit of the goal.
I don't think you're wrong, just a slightly different perspective.
P.S. Also, what gr3yh47 said. That's a whole different meaning of "hustle" that's probably not meant by people who describe themselves that way but which often applies to them nonetheless.
Am I using it right since it simply means work hard?