Depends on where the 12v was drawn from. If it was connected to the 12V cigarette lighter port (that thing has a 15A or 30A fuse in my car) that should be expected load, but maybe not 2+kW drawn constantly for hours directly from the battery's leads.

Anyway the Tesla doesn't generate power during driving like a regular car does, so the 12V power is always topped up from the main Lithium battery and the DC-DC converter needs to be reasonably sized to accommodate eg. 600W supply. If power was taken from the regular port than i would count it as regular use (eg. when camping i would count on my car to charge things, even if it uses fuel and generates 0 km/miles.)

There's another catch:

What if you keep jump starting another car with leads directly attached until the LA battery is depleted? That is a very common scenario and Tesla should size the electronics correctly or make it resilient for that use.

Last I checked, Teslas are not intended to be used for jump starting other cars.

Same with most hybrid cars. Toyota/Lexus strictly forbids this and is have denied warranty claims.

It’s also clearly stated on the owner manuals.

I completely agree. If this were just using a cigarette lighter connector or USB-C, I'd have a hard time seeing the issue. In all the Teslas that I'm familiar with, both are connected behind an electronic fuse to protect the car and the device.