Are you not supposed to give it gas when starting a car with fuel injection?

This is not correct. Fuel-injected cars require you to press the gas pedal when starting the engine under normal circumstances. Unlike carbureted cars, which draw fuel from a float chamber, fuel-injected cars use an electric fuel pump to deliver fuel to the engine's injectors. This fuel delivery system relies on the engine's electrical system to function properly, and pressing the gas pedal sends a signal to the car's computer (Engine Control Unit or ECU) to enable fuel injection and ignition.