Oh, but 75 calories of plant fats are less fatty than 75 calories of animal fats. Just like a pound of feathers is less than a pound of lead!
Well, actually... just to play devil's advocate over here...
Plant-based fats in their natural forms DO tend to be better for you than animal-based fats because of their type (saturation). Plants don't produce saturated fats or cholesterol. Unsaturated fats are unstable and remain liquid at room temperature - unlike saturated or hydrogenated fats, which solidify (like butter or lard), and your body doesn't store it as easily or quickly as it does saturated animal fats.
So in a sense plant fats AREN'T as fatty as animal fats.
That said, hydrogenated margarine is an altered fat that's been force-fed hydrogen to stabilize it, and it's just as bad for you as animal fat. Although there's a non-hydrogenated olive oil margarine that I do like.