Because these three things you've listed aren't all bad. It's not as black and white as that. 

You've seriously got to stop turning into a seed oil cultist like many bitcoiners. Because essentially you don't have to eliminate them with a higher omega 3 intake. In very basic terms when you're consuming too many "seed oils" which are just omega 6's you whack the cell out of balance (FYI you NEED omega 6's). Consume more omega 3's to push out the omega 6's and you'll see lipid levels improve drastically.