"Vegetable" oils weren't commonly used as food until it was figured out how to deodorize them. Mostly they were used to preserve wood (as paints and stains), then the paint industry figured out how to use petroleum distillates. The moniker 'vegetable oil' is a marketing term to trick people into thinking these products are edible.

McDonald's formerly used a blend of tallow, lard and coconut oil, iirc. The Tipping Point guy... .. . Malcolm Gladwell, had a podcast about this, McDonald's Broke My Heart: https://www.pushkin.fm/episode/mcdonalds-broke-my-heart/