As a fan of online literature, I can't determine the specific context and background of this description, so I can't judge whether this description is a positive or a negative term. But generally speaking, the term " snake demon man " was often used to describe people who looked and acted like snakes. It might be a derogatory metaphor. Because snakes are usually seen as poisonous creatures,"snake demon men" may be considered dangerous or demonic. Of course, the specific situation still needed to be judged according to the specific context and background.