Most so-called "vegetable oils" were traditionally used as drying oils. This was before the paint industry figured out how to use petroleum distillates in their products in the mid-20th century.
Linseed oil was renamed "flaxseed oil" when the market for stain made with linseed oil dried up.
Containers of vegetable oils typically develop a sticky film on them, due to the drying oil effect.
Maybe I'm not viewing this with the proper historical context, but I don't understand why you are saying the market for linseed oil has "dried up" for non-food uses. Boiled linseed oil, which contains linseed oil, is probably the most common oil based finish for woodworking.
I also looked at this website about "Linseed oil market analysis" [1], which shows that Paints & Varnishes is still the largest user of linseed oil. Then processed foods, then pharma, then cosmetic, then flooring (which is probably also as a finish).
I'm eye-balling the graphs because they don't have a table, but it looks like processed foods is only about 20% of the market. That might be a lot, I don't know, but it doesn't seem fair to say all this excess linseed oil is going into foods because there is no other use for it.
... strictly speaking you’re certainly correct that there is still a significant non-food use for linseed and the other vegetable oils. But there were only limited food uses for polyunsaturated oils before deodorization and hydrogenation techniques were figured out in the early-mid 20th century. People might [have] measured out a tablespoon for their cooking pan, whereas today people use these oils prolifically.
