Different additives have different colors, it is probably not as robust as our favorite oils. The base oils are clear themselves, the PI package gives most oil it's color.
Often times mower oils carry obsolete API ratings or API SG, which is pretty light on additives, did you see the API rating on the bottle wording?
If you're looking for one of the best over the counter oils for a mower I like Mobil 1 High Mileage, it's API SL rated with extra ZDDP. API SL is a good rating category for air cooled mowers. Quaker State defy also works great if you don't like synthetic.