important to keep in mind that conventional oils (non organic/biologique) are going to contain pesticides, since they are applied to the seedy/oily parts of the plant and may be accumulating in the oils themselves due to solubility. Now that's why REFINED oils are quite common (many veggie oils are refined whereas olive is not, one must check the label) but that's no reason to eat them. sunflower, hemp, avocado, whatever: when an oil is superheated and fractionally distilled to remove the undesireable elements such as off aromas and foriegn pesticides that oil undergoes drastic changes to some of its chemistry that according to Udo Erasmus leaves 1% permanently changed into something unique and possibly undigestible to our cells. (read that in a magazine, can't find the source right now). Furthermore refining only removes 50% of the pesticides from the oil, and by superheating it there is the strong possibility that the oil becomes rancid by the time you buy it, since extreme heat is not the most stable place for an organic molecule like that. And phytonutrients in plant matter that make it into the oils are likely to be beneficial to the consumer of them, being part of the total 'food' that the oil really is (extra virgin olive oil is a good example of this. the unfiltered stuff tastes great and it contains more of those green particles which are antioxident and protect the oil from going rancid). Soy is said to be one of the most polluted edible oils out there due to the seed pods being the source of the oil and they are heavily sprayed.
fats are an important thing to consider when it comes to diet, since we the people evolved eating that now notoriously fadish ''paleo' diet which is calorically places fats as being something like 40% of our total calories. IF you eat good oils all the time you can cut back on carbs, which more and more studies are showing to be at the source of a very many great pathological ailments, from diabetes to high cholesterol, obesity, inflammation, etc. too bad good fats taste real good on carbs! love my bread n olive oil, mmm!