Va= Plane will stall before structural damage occurs if any control surface is given immediate and full deflection in any direction. Obviously, the immediate pitch up is the one that will induce the most force and is typically the one demonstrated.

Vno= Green Arc, means life is good. The structural integrity of the airframe should be able to handle normal operating loads in smooth air, as well as light-moderate turbulance(although slowing to Va in moderate isn't a bad idea). Not to mention, most planes out there usually don't have the engine power to exceed Vno in straight and level flight, so another reason it's refered to as Normal Operating. The statement "Even Suprise Turbulence could break up an airplane" is incorrect, unless it would be "severe" turbulence, and you most likely just flew into a thunderstorm.

If you are operating in the Yellow Arc(Vno-Vne), then the onset of turbulence in that speed range could potentially damage the airframe, but even then there are many factors involved that don't guarantee damage will occur(but over time with repeated high-speed flight into turbulence will cause accelerated fatigue).