OK, maybe there is disagreement in terms. If one step on the gas the vacuum increases in the intake manifold and thus the fuel pressure regulator increases the pressure in the rail to get more fuel through the injector. Agreed?

If there is less vacuum in intake manifold when you press the gas why would air flow into it? Vacuum or difference in pressure (atmospheric air pressure - vaccum) increases rate of air flow, if there is no difference in pressure there would be no air flow.

Just like saying if there is no voltage (difference in pressure) there is no current flow (air flow) in a circuit.