Or at least that's the source of confusion for me, maybe the terminology is different at this level.
Others have mentioned it is.
The reason why 'asserted' is used is that signals at this level are basically analog. The circuit that asserts a signal is, fairly literally, being assertive, and there are all sorts of commonly used options: Pull-ups and pull-downs, either one in either weak or strong (assertive) form.
Connecting a strong pull-down to a strong pull-up represents a short circuit, but having one circuit assert a logical 1 while the other circuit on the same pin holds a weak pull-down (presumably, in this case, 0), is a pretty common configuration.
The most important thing to keep in mind, working with electronics, is that all pins must be connected to at least a weak pull-up/down, which can be as simple as an MOhm-class resistor connected to ground.
If they aren't, then the gate is floating -- and a floating CMOS gate can easily reach states where the gate itself is short-circuiting, since they're made from a transistor pair connected to both ground and power. (As is necessary to support both pull-up and pull-down.) If that doesn't destroy the gate -- check your datasheet -- then, at a minimum, it'll still waste power.
The majority of common microcontrollers (e.g. Arduinos) will allow you to configure the gate with a internal weak pull-up/down, to let you avoid connecting every single pin, but you shouldn't assume that it's configured that way out of the reset vector. Nor that such an internal pull-up even exists.