"Hi, what are your Transform values ?"
Is it not shown above on the screenshot ?
Sorry, my fault ! For some reason the image shown clipped on my screen. I restarted the browser and now is correct.
First of all, Rotation axis may be a bit different from common sense: X means that items are rotated along the X axis (which goes from left to right on screen), so really they move upward/downward. In same way, Green (Y axis) rotate them from left to right.
Regarding colors, with your range settings (-90º to 90º, both for X and Y), pure Red has RGB:255,0,0. So, Green component is 0 which means -90º on Y. For that reason your items are facing to left with red and black colors.
Best way to understand how it works, is testing combinations interactively with a Color selector. You can use the attached scene for that.
You can see what RGB values are generated when changing Hue/Sat/Value.
I hope that helps. Please don't hesistate to ask is something is not clear.