Trans-fats, or hydrogenated vegetable oils, are the only fats I believe important to eliminate from our diet. They're of no value to us, only the food industry, as you say. I'd rather have the longer shelf life, if you don't mind - your processed food can rot!
I don't think 20%-30% calories from fat is very clever though. We've never been a low-fat species, until the food industry started making big money at it 30 years ago. Diabetes and obesity have increased exponentialy in that same time.
I'd say most people should be eating more fat, not less. 'Eat more!', now there's a line to get some attention, eh?
All the best,