Earlier quoted context omitted.
One of the concerns is nitrogen oxides (mostly nitrogen dioxide, as I recall) from high temperature combustion. Car engines attempt to limit combustion temperatures (usually by adding some exhaust gasses to the intake air) to reduce its production. Ventilation prevents it from reaching hazardous levels from a gas stove; induction does not produce it.
The point is most of the harm comes from the cooking, not the gas. Classic over optimizing. Might as well ban Teflon while you’re at it (the eu did this, as it’s harmful)
So you can simmer a stock for a couple hours without needing to run the fan (and cook most anything under 300 degrees or so), and with the fan off you don’t lose nice conditioned air from inside.