I would argue that there are two main reasons why it is important to understand that people experience historical events in different ways. The first reason has to do with historiography while the second is more practical.
First, it is necessary to have this understanding if you are to be a good historian. If you think that everyone experiences events in just the same way, you will tend to be somewhat unthinking and uncritical in your work. You will assume that your own way of thinking about an event is the only way to think about it. You will then write history only from your own point of view. The history that you write will therefore be very limited and incomplete. It will read more like a chauvinistic account than an objective history.
We should not, however, think that only historians need to understand this idea. Instead, it is important for others to understand it because this will allow them to have a better grip on the possible ramifications of a given event. Major historical events tend to change the ways in which people think. They can, therefore, affect the ways in which those people act. If we do not understand this, we will not be able to predict how others may react to major historical events. If we cannot imagine others’ thinking, we cannot anticipate their actions. For example, we might think of things like the Opium War and the Boxer Rebellion as insignificant events that are buried in the past and are not important to anyone today. If we think this, however, we miss out on the fact that many Chinese see these events as examples of Western imperialism. We miss out on the idea that they think that the West is still trying to exert hegemony over China. This makes it hard for us to understand their actions.
Thus, both historians and laypeople need to be able to understand that different people can experience major historical events in different ways.
It is important to consider major events from history through multiple perspectives so that one can gain a more thorough and objective understanding of what truly occurred in the past. It is crucial here to note that all accounts documented are often driven by an agenda that the creator himself or herself wants to push for. For example, a historian may write in a way that would best allow his or her own argument to be presented, while the state may manipulate historical evidence to allow a certain image of a particular issue be perpetuated amongst the public. Everyone has their own biases while writing and are more often than not driven by their own personal agendas to do so. Therefore, to obtain a more truthful, accurate and objective interpretation, we have to account for the viewpoints of different writers and ensure that the information we have gleaned from these sources is reliable and trustworthy. It is only then that we can form our own complete interpretation of the past.
There is a famous saying that goes something along the lines of, the winners write the books of history. If we look at what we are taught, history is literally, "his story," the white man's perspective. Everything we were taught was from the perspective of the winner. The winner takes it all, and writes it in the way that glorifies him the most.
But there is more to that, the other perspectives. The losers, the observers, the other victors. Each event is experienced differently by each person involved. For some, it may be minor - some land gained, some money made. But for others, it may be major - sickness that kills your whole population, loss of food, loss of a home. And for everyone it will be life-changing - everything has changed what we call history. It is your job to find out what story you want to believe.
There are some facts. It's how you use them to tell a story. It is how you piece together each side that makes you learn, and allows you to prevent a repeat of the same mistake.
Understanding that people have biases is important in all feilds of study. Being aware of how, say, the author of your test book may have understood history differently from yourself can be very helpful. In general is seems the winners write history. This often results in someone's story not being told, or being told incorrectly. A good example of this is Native Americans. For many years their contributions to American history were minimized or left out entirely. This problem has been remedied somewhat over the past decade but could still use improvment.
When analyzing historical texts (especially primary sources) it is important to ask questions such as: What's their angle? What might they be leaving out? Who might have a different prospective?
It is important that people should experience history in different ways because we dont want biased opinions. For example, if you take American history in America, the events are told through a biased perspective that glorifies America. You need to understand that not everything is as good as it seems. For example, we were the heros who fought against Germany and defeated them in World War I. Although through Germany's perspective we might be seen as villians as we crushed them, and destroyed their economy, and had a unfair consequences of their loss. Inflatation was so high, Germans needed wheelbarrows of money just to go to the supermarket. The struggle of Germany is never really looked at when told through America, because we focus on the good of America. For example, the US sees the bombing of Hiroshima and Nagaski as necessary for ending World War I, while Japan begs to differ. You will never understand history if seen through biased eyes, you must view history from different perspectives to truly understand it.
In order to understand history you have to understand the event from everyone's point of view. Just because one group of people experienced something good doesn't mean everyone did. For example, manifest destiny. This was a good thing for the American colonies as it helped us gain new land, new resources, gave us new states, etc. However, for the Native Americans who we took the land from it wasn't as great.
If historians didn't see both the good and bad in a situation we might end up making a bad decision in the future. Only seeing our opinions and closing our minds to others ideas may cause us to miss a great opportunity and make a poor decision.