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)
I'm not sure whether that's true (nitrogen dioxide can be pretty bad), but I am sure that ventilation is the answer either way. I suspect the main motivation for the ban is to be able to shut down the gas lines in the future because their existence results in methane leaking into the atmosphere. Health concerns might help them sell it ("think of the children" tends to be pretty effective, politically).