One potential cause of fat villainy is displaced anger against sugar. A study's highlights here show that sugar is just as damaging if not moreso than dietary fat intake, and that the brain gets pleasure from consuming sugar just as much as fat.
Trimmed fat has many uses, not excluding soap making. A really interesting chemistry read of how fats become saponified can be found here. Soap made from animal and vegetable fats contains glycerine, a natural moisturizer, where commercial soaps lack this valuable by-product. The glycerine is removed via a chemical process, and sold to be used for , but since glycerol is a by-product of manufacturing biodiesel, it isn't worth as much as it used to be. The glycerin-devoid soap is milled, or ground down, and rebatched into what we call bar soap.
There is quite a bit of research that shows that people can't survive without dietary fats. Most people are familiar with the concept of Omega-3 and Omega-6 fatty acids being good for us. Other fats are necessary as well, as this post I wrote a while back demonstrates. Indeed, too much protein with too little fat has been known to cause a dietary phenomenon called Rabbit Starvation, sometimes known as protein poisoning. It happens in the absence of carbohydrates and fat, as the name implies. The liver can't effectively metabolize the high amounts of protein, and the kidneys are inefficient when blood urea levels are that high. Death soon results. The prevention? Eat a wide variety of foods, including natural carbohydrates and fats.
In summation, blaming carbon molecules for poor life choices is like blaming guns because psychopaths use them.