(I'm sorry I hate doing these point by point breakdowns, it lacks narrative structure and flair, but I'm tired...)

but it is small enough to be considered an open circuit for engineering purposes.

The current flowing when you complete the circuit with with your hand is about 0.2 miliamps (measured at ~47,000Ω resistance so I rounded to 50k). If any engineer is considering that an open circuit they should be driven through the streets in a waymo I would very much like to see the application in which they consider that an open circuit because none is springing to mind (outside of clear outliers like some of the really weird switches used in high voltage electronics which I can't even remember the names of).

Shorts are unintended low impedance paths.

That is one type of short, yes, however if we look at the closest thing we're going to find to a broadly accepted formal definition (the one from wikipedia:)

A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in a current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion.

We can see that it is not actually a requirement to have a circuit with low/no impedance; it's just a common form a short takes. The actual requirement is a circuit with lower impedance than the intended circuit. This makes sense of course: a short across a signal wire is obviously not going to dump the full potential of an entire system, only that portion which provides current to the shorting circuit. It would similarly still be considered a short if the conductor shorting the signal wire were a high-impedence resistor that was causing a false signal - so long as it's enough to trip whatever sensor is at the other end, it would be a fault caused by a short circuit. In the case of a car battery, the leakage current is part of an absurdly low current circuit (something like 30 picoamps) which you are shorting when you make contact with the terminals. The difference between a circuit with kilohms of resistance and one with near gigaohms of resistance is phenomenal.

However at the risk of still being right, let me say that this is an incredibly pointless semantic argument to be having. Yes, technically, you are shorting the battery. In a more formal setting I probably wouldn't have phrased it like that in an effort to stave off the chance of a tedious argument like we're having right now; however this is a shitpost community so I figured brevity instead of defensive technical clarity was the ideal course of action.

Misjudged that one, didn't I.

(Edit: clarity, removed horny joke. This is no joking matter.)

A quite reasonable argument could be made that a battery simply sitting around is only connected to one circuit (itself thru the air) and thus there's not an "unintended" one it's also connected to that could be considered a short - but really, my unstated point this whole time is that this is not a usefully rigorously defined term. The definition on wikipedia is as close as we'll get, and it's extremely broad by it's nature.