They could fulfill all the needs of most masters. They were loyal and eager to please, just like a dog but in addition they were intelligent, just like humans. They were advertised as the ultimate companion animals.
These anthropets soon became very popular. With the best lawyers money could buy, they rammed this machination through the courts and were free to monopolize the anthropet market. But because they were sentient and thus were capable of giving consent, bestiality laws didn't apply to them. Even though these animals were sentient, Genetech went to court to prove that since these animals were not humans they didn't have a soul so they could legally be owned as property.
In 2049 Genetech genetically engineered and patented the first anthrodogs as companion animals.