There may be many reasons why people don't keep cats with yin and yang characteristics, but here are some possible explanations:

Cultural tradition: In some traditional cultures, the yin-yang cat is considered an ominous sign. This concept may be related to people's belief in mystery and supernatural forces.
Health issues: Having two personalities (one male and one female) can lead to several health problems, such as endocrine disorders and immune system imbalances. These issues can cause illness or even death in cats.
Psychological factors: Some people may consider yin-yang cats to be unsettling or ominous animals and therefore be unwilling to keep them. This psychological factor may stem from a fear of the unknown and anxieties about uncertainty.
Social context: In some regions, hermaphroditic cats may be considered illegal or unacceptable by society. This may be because people consider them immoral or unacceptable pets.