This is true if you are using organic oil. The preservatives in name brand oils are designed to kill you. They are designed to limit reaction with oxygen which is precisely  what the cell needs. With no oxygen, the cell gets cancer or dies.

Back in the early 1900s and before, many (most?) middle and upper class Americans cooked with, and used uncooked, virgin (unprocessed) coconut oil. This virgin oil was stable (not becoming rancid) at room temperatures for as long as 1 year. It was healthy to eat, mirroring the south seas islanders, who had little if any heart disease. It was only after big industry started processing it, and the medical started lying about the difference between processed and virgin, that it became as unhealthy as processed corn and vegetable oils - the stuff containing the trans fats and the "bad" saturated fats... the stuff that we eat today.

All this was done to promote corn and vegetable oils, oils which are hard to get at without processing. It is the processing that gets the oils out of the corn and veggies. But it is, also, the processing that makes them unhealthy for you. Because coconut oil can be gotten out of the coconuts relatively easily, without processing, it is good for you. But processed oils are still way cheaper.

So it's all about money. Who cares about your health.

Of course not all cooking oils are equal.  Those who cook with lard are probably going to get clogged arteries.

Speaking of olive oil, if you want to make a healthy snack try popping pop corn in it. It gives it a buttery flavor and is good for your heart.