Touch screen stylus

[CanBeDone]

Marv, whether you have a capacitive or resistive coupling between pen and camera screen, you need a voltage, and a current to flow, to embody a signal. The magnitude of the current is determined by the voltage you create by moving the tip across the screen (i.e. electrode 1 of the camera), and the resistance between electrode 2 (either the body of the camera, or another electrode built into the screen). Where does the voltage come from, if there is no battery? I am sure a physicist like you does know about influence, i.e. the separation of electric charge due to moving two materials (which may be conductors or insulators) close to each other. And once you realize it is influence that creates the voltage, you'll know that voltage will be in the thousands of volts. And since the current will need to be in the micro- or milliampere range, so that the electronics inside the camera is protected from overvoltage, there has to be resistance in the megohm range. And megohms cannot be reliably measured with an ordinary ohmmeter. You need a megger (a mega ohm meter), i.e. a device that injects thousands of volts into the circuit-to-be-measured to get a signal of suitable size, and not the roughly 10 volts of an ordinary ohmmeter.
And look at the color of your pen: it's metallic, and that means the plastic contains some aluminum powder, and its resistance is no longer in the teraohm range of pure ABS or polystyrene, or whatever the body of the pen is made of. And your chopstick, being wood, will contain some salts, and thus will have resistance in the, maybe, gigaohm range, too much to give a meaningful signal but not enough to make wood a trustworthy insulator. Have a look at e.g. https://woodwoodland.com/does-wood-conduct-electricity/ for a table of resistivity of some materials.
It's not difficult to understand once you start seeing your device in terms of SIGNAL=CHANGING VOLTAGE and the consequences this has for the upper and lower limits of current required to affect electronic circuits.