Find out the idioms related to dogs [the more the better] and tell me why there are so many derogatory meanings.

The dog's blood drenches the head, the dog steals the mouse, the dog's tail steals the mink, the dog's tail continues the mink, and the dog's heart goes away.

Dogs continue to be crowned, dogs continue to be crowned with gold, ferrets and dogs are soaked with blood, and dogs are heartless.

Dogs see people bite dogs. Lv Dongbin hangs sheep's head and sells dog meat to hang sheep's head.

Dogs are not as good as dogs. They don't eat dogs, pigs don't eat leftovers, and dogs don't eat leftovers.

A dog chasing a mouse can't spit ivory. Dogs can't fight each other.

Draw a tiger as a dog, a tiger, a dog and a dragon, but don't become a dog, a fox, a dog or a thief.

Fox's friend, fox's friend, fox's friend, rabbit-cooked dog, chicken, dog, intestines.

Chickens fly dogs call chickens fly dogs jump chickens fly dogs go marry dogs marry dogs chase dogs.

Marry a chicken with a chicken, marry a dog with a dog, chicken with a broken dog, chicken with a thief, chicken with a dog barking, a sly rabbit dies, and a running dog cooks.

I think most of them are derogatory because of the following points:

1: Dogs eating shit left a very bad impression.

This street used to be full of mad dogs.

Dogs and wolves look alike. Out of hatred for wolves, it was transferred to dogs.