And how is that relevant to the alleged complexity of building an AM radio vs an FM one? The point was that the latter is easy, not complicated. The FM transmitter is so easy to make that you can make one by accident - if there's a non-linear element in the rf part.
Its about the simplicity of the circuit. The components are available for any electronic Technician.
Use an amplifier is not a basic circuit. Resistor diode capacitor cable and power source are the basic of electronics