At my most recent workplace, the CNA instructor was fantastic---enthusiastic about what she was doing and communicated her excitement to her students. My son went through her class a year ago, and he's still working for the same nursing home plus was offered a second job at another one just because he was recommended by this instructor. So no, not all of them are burned-out nurses.....you just happened to be unlucky.
I should mention that sometimes, what may seem to a CNA to be abrupt and impersonal behavior in a nurse is a product of stress, which could be due to almost any situation. I'm probably one of the "nicest" nurses around (or so my aides have always told me), but in an emergency, my speech becomes clipped and I tend to be very direct because at that time, I don't need people to understand why I want something done---I just want them to do it STAT! I will always apologize and explain later, but when I've got a patient who's crashing and the EMTs are on their way, I don't have time to say "Oh, Mary, could you please find Jane and ask her to get me some vital signs on the lady in 303C, she doesn't look too good."
And yes, there are those nurses who are bitter and nasty, and they should hang up their stethoscopes and go do something else because it's obvious they don't like nursing. But I don't think the six nurses you've cited as being negative are representative of us as a whole, so please don't judge all of us by them.