This is hardly what I call Winnebago's "policy". Seems like more of a common-sense recommendation that most people already know.
Feel free to exert yourself worrying about the heavily diluted and often ineffective consumer pesticides that someone "might" spray around the edge of their camper...but pay no mind to the diet soda you drink which contains deadly chemicals which you can't even pronounce, or the box of crackers you buy with numerous chemical-sounding ingredients, or the open-air produce in your grocery store that people walk by all day sneezing on it, coughing on it, handling it after petting their dog in their shopping cart...etc.