My car can act like a tractor. That does not mean it is a tractor. It is a car. 
Perhaps you can clear up the confusion on the sun.
If the sun is not a spotlight but acts like a spotlight just how does it act ?
I am assuming that the flat earth definition of the sun is :
(1) Is the sun the shape of a disc or is it the shape of a sphere ?
(2) Is the sun 3000 miles from the earth or is it at some other distance ?
(3) Does the sun just shine downward on the earth or does it shine in all directions ?
(4) If the sun shines downward is this like the beam from a spotlight or flashlight ?
(5) Is this beam in a well defined circular pattern like a spotlight or a flashlight or is it in some other shape like an oval ?
(6) If (4) and (5) are true is there some kind of focusing condition to form the whatever it is : "spotlight" or "acts like a spotlight" if (3) is true ?
Please provide a detailed description of the flat earth sun. This might clear up these questions. Thanks.