They being the people who first started creating and marketing these seed oils for consumption. What the oils really are, are hydrogenated seed oils. Note that

They being the people who first started creating and marketing these seed oils for consumption. What the oils really are, are hydrogenated seed oils. Note that article mentions both naturally pressed plant oils, and the hydrogenated oils, but then a point that mentions what oils are only allowed to be called vegetable oils: In the US, the Standard of Identity for a product labeled as "vegetable oil margarine" specifies only canola, safflower, sunflower, corn, soybean, or peanut oil may be used.[8] Products not labeled "vegetable oil margarine" do not have that restriction. Again note none of them are vegetables, they are all seeds, and go through a hydrogenatation process which makes them brittle. Again all mentioned in the article you linked to me. Also interesting is that right at the end of the article is how some countries insist that labelling them vegetable oils isn't enough and that the true ingredient must be listed. Also notice they do rename things for marketing, like canola instead of rapeseed (as they though rape wouldn't sell). I guess "hydrogenated seed oils" doesn't sell as well and so they called them "vegetable oils".