If the attribution is vague or nonexistent, you are right to reject or mistrust the material. If no source is given, be doubly suspicious. Distrust generalizations, along with ideas or arguments based on them. Categorical statements about groups or individuals are rarely valid. Life comes in too many varieties.
Nothing is true for everyone.
Analogy is notoriously unreliable. Analogies are ways of illustrating points or issues by comparing them to something with similar characteristics. It assumes that because there is a relationship between two things, they must therefore be alike in every way. Running a business might, in many ways, be like a medieval Japanese Samurai sword-fight. But it isn't a swordfight, and it could be dangerous to make business decisions solely according to the principles of ancient Bushido.