One reason why they say history must be read is their belief that "history repeats itself". The idea is that the lessons of the past would be helpful to us in the future. We learn from history about the circumstances that usually lead to war and about how great civilizations rise and fall. We can be on guard against a repetition of these circumstances and this, we are told, is one of the "uses" of history.
The same events are repeated kalpa after kalpa. According to our sastras, the Ramayana, the Mahabharata, the Bhagavata, the Dasavatara (the story of the ten incarnations of Visnu) and the Puranas are re-enacted kalpa after kalpa. Here too we see history repeating itself.
Have we in reality learned any lesson from history, I mean from the history taught in schools? No. We learn how such men as Cenghiz Khan, Timur, Ghazni, and Malik Kafur appeared from time to time and caused devastation in various countries and how they massacred innocent people. But by reading accounts of their infamous deeds have we been able to prevent the appearence of such scourages again? Hitler and Mussolini rose to perpetrate the same kind of outrages on people.
We are witness in our own times to governments losing their support because of charges of bribery and corruption made against them and other malpractices ascribed to them including partisanship and nepotism. When one such government falls, another group forms a new government and they too lose the support of the people in the subsequent elections for the same reasons. Here is an example of our failure to learn any lesson form history.
History must be taught along with lessons in dharma; then alone will it serve the purpose of bringing people to the right path. The Puranas do precisely this.
History contains no more than accounts of monarchs and other rules in chronological order. It does not give importance to their moral character : whether wicked rulers suffered an ill fate or whether just and righteous rulers earned a high place. According to the law of Karma, Isvara determines the fate of people on the basis of their actions, meritorious and sinful. Such justice is not necessarily meted out during the lifetime of a person. The fruits of a man's action are reaped in subsequent births. It is not the task of history to deal with such questions, nor do historians have the capacity to inquire into such matters. Whether a wicked ruler like Hitler was consigned to hell on his death and whether he had a lowly rebirth is a subject for the Puranas. Those who composed these texts had the reqisite insight to deal with such questiions; indeed the very purpose of these stories is this, to impart moral lessons. From history we do not derive any edification.
The Puranas are also, as I said before, history. Besides, they contain lessons in papa and punya (demerit and merit). In fact, their choice of stories and narration are such as to bring people closer to the path of dharma. Again, the Puranas contain accounts of individuals who by virtue of their steadfast adherence to dharma attained to an elevated state in this birth itself. At the same time, they also tell is about persons who, by their acts of adharma, came to harm in this very birth itself. There are in fact no Puranic stories that do not contain some moral lesson or other.
"The experience of the past narrated in history are a pointer of future events. The stories of good men who performed virtuous deeds and benefited from them should be a source of inspiration for us. In the same way, the stories of wicked men who brought evil to the world and themselves suffered on account of their acts contain a warning for us". Is the stufy of history really usefull in this way? It is not. To improve ourselves morally and spiritually we must turn to the Puranas.
The purpose of the Puranas is not to give [as history does] a chronological account of kings or their quarrels without imparting lessons on good and evil. We do not need such history since it does not contain any guide for the condcut of our life. History must be capable of bringing us Atmic rewards.
The Puranas too deal with the lineages of various ruling houses. They give accounts of dynasties descended from the moon and the sun (candravamsa and suryavamsa) and contain list of successive rulers of varous kingdoms. But in most cases only the names of rulers are mentioned or only brief references made to them. Detailed accounts are given only of rulers whose lives have a lesson for us. For instance, the Bhagavata tells the story of Uttanapada, the father of Dhruva, and of Dhruva's son, but only very briefly. However, the story of Dhruva himself is told in detail, Dhruva who is an example for all of us in devotion, determination and courage.
English historians dismiss the Puranas as false. But on the pretext of carrying out impartial research they twist history to suit their ends like, for instance, their "divide and rule" policy. It is in this way that they have propagated the Aryan-Dravadian theory. If the Puranas are a lie, what about the history written by these Englishmen? Efforts are going on to reconstruct our history. But prejudicial acounts cannot be ruled out in these new attempts also. What ever claim the historians make to impartiality, it is hard to say how far the new history (or histories) are likely to be truthful.
Vyasa, who composed the eighteen Puranas, the great men who wrote the various Sthala Puranas, and the Tamil author Sekkizhar were unbiased in their accounts.
It is not right to view history merely as an account of the rise and fall of empires or of wars, invasions, dynasties amd so on. Each and every subject has a history of its own. But we find that political history is given a dominant place. The emphasis in the Puranas is on dharma and, incidently, they also deal, in a subsidiary manner, with the ruling dynasties, with holy men as well as with ordinary folk. They contain details also of cultural life, the arts and the sciences. The thrust of the Puranas, however, is dharmic and Atmic.
For a general background, please see here