> It seems that if I stick my finger in the hot socket, there is still a path via me to 0 voltage (the ground)
Over-simplified, but you need a complete circuit. In your example you say that voltage is across you - live at a finger and earth at your feet. But earth is not connected to the circuit, so there's no complete path. That's why the article talks about sticking rods into the Earth to create a ground connection. Now there is a complete circuit. (And this would be across your heart - the current flows through a finger, your arm, your heart, down your leg, and to Earth. This is especially dangerous, and is the reason you see test engineers working with one hand in their pocket. Not having two hands connected to live equipment means it's harder for a voltage across the heart.)
There's another thing to mention though: Imagine wearing rubber boots, on a dry wooden floor, and jabbing a metal rod into the socket. That's still risky, because your body will act like a capacitor and the charge can be fatal.
Over-simplified, but you need a complete circuit. In your example you say that voltage is across you - live at a finger and earth at your feet. But earth is not connected to the circuit, so there's no complete path. That's why the article talks about sticking rods into the Earth to create a ground connection. Now there is a complete circuit. (And this would be across your heart - the current flows through a finger, your arm, your heart, down your leg, and to Earth. This is especially dangerous, and is the reason you see test engineers working with one hand in their pocket. Not having two hands connected to live equipment means it's harder for a voltage across the heart.)
There's another thing to mention though: Imagine wearing rubber boots, on a dry wooden floor, and jabbing a metal rod into the socket. That's still risky, because your body will act like a capacitor and the charge can be fatal.