You may be correct in the case of some sausages.
However, to brand all sausages as unhealthy is wrong. It all the ingredients it contains are acceptable as part of a balanced diet. If you were to live off a diet of sausages and sit on your ass all day, you'd get fat and suffer from malnutrition. But then if you were to do the same thing using bananas, she same thing would happen.
You should note that, when considering a whole lifestyle/diet, too little fat is as dangerous as too much.