The secrets of creation are mentioned in our holy Puranas, and it was also told by the great Shaivite Saint Sri Pujya Sri Guru Devar, who lived in Varanasi during the 20th century AD, and he is an incarnation of Lord Shiva. Every one of us would be wondering that why Lord Brahma is creating us in different forms, and in different classes. The main reason for that is he is doing it according to the Law of Dharma. Similar to the humans who are following certain rules and regulations, policies and practices, they are also doing like that. No one can forbid those rules and regulations and even by the god.
According to the statement given by Sri Pujya Sri Guru Devar, God is creating each and every living being in a different manner, as per the strict laid down rules and regulations. God would not do his creation work according to our wish, and no one can change this, and no one can question about this also. A human being is getting either favourable or unfavourable results based on their karmic deeds only. If a person does good acts in his life, then he would get a good birth, after his death, or he may reach the place of heaven. Whereas if a person does bad acts in his life, then he would get a bad birth in his next birth, or otherwise, he would dwell in the hell, and would suffer from all sorts of punishments in the world of Lord Yama Dev.
If god creates all the living beings as alike, and if everyone does only good acts, then there would be no place in the heaven and the hell would become empty, and there would be no work for the creation god Brahma also. Hence in order to maintain the correct balance, god is creating both good and bad ones, and based on their deeds, they are either awarded or punished for their acts.
We cannot blame the god, since he is not doing this type of activities willfully. God is also getting worried about the sufferers in the earth, and he is also trying to uplift the sinners by making them to realize the significance in worshipping the god. For certain things, we don’t get proper answers. The only thing what we can do is, to keep sincere bhakti on the god, and to fill up with full of spiritual thoughts in our mind for ever in our life.