Outsider view of history of a nation maybe responsible for cultural decimation.

Historical disasters in this nation as it was written by authors funded by outside  institutes 

An outsider's historical view can indeed be a source of cultural decimation by misinterpreting, misrepresenting, or selectively narrating a culture's history, which can in turn undermine its identity and self-perception. While the outsider perspective offers a valuable, objective lens, it can also lead to the marginalization or erasure of a culture's own internal narratives and values.

The Perils of an Outsider Perspective 

Imposed Narratives- An outsider historian, lacking deep cultural understanding, may apply their own cultural frameworks and values to the culture they are studying. This can lead to the creation of a historical narrative that is anachronistic or entirely alien to the lived experience of the people. This "imposed history" can supplant the genuine, often more complex, native narratives.

Deciding What's "Significant"is a challenge especially when it is related an opinion about others. History is not just a collection of facts, it's a story told about those facts. An outsider historian, with a different set of values, may decide that certain cultural practices, oral traditions, or historical events are insignificant or even primitive. By excluding these elements from the official historical record, they contribute to their loss and devalue them for the culture itself.

Language and Interpretation continues to be aa area of perpetual debate. Non-translatables are particularly subject to mis- interpretation or misappropriation.The nuance of language is often lost on an outsider. Words that are deeply sacred or culturally loaded may be translated into terms that carry very different connotations in another language. For example, a spiritual figure might be described as a "shaman" or "witch doctor," terms that can carry colonial or pejorative baggage. This linguistic decimation strips the culture of its own precise and respectful terminology.

The Dual-Edged Sword of Historical Objectivity 

While the risks are real, an outsider view isn't inherently destructive. It is a dual-edged sword that can also provide immense value.

Challenging Myths is one of them. An outsider can approach a culture's history without the emotional and ideological baggage of internal narratives. This can allow them to critically examine and deconstruct national myths or self-serving stories that may not be supported by evidence. However, they do carry the baggage of external narrative often forgotten under the banner of academia.

A historian from a different culture can place a society's history within a broader global or regional context that the insiders may not see. This can help to illuminate historical connections, influences, and dependencies that enrich the understanding of a culture's past.

Documenting the vanishing is certainly the most important outcome. In some cases, an outsider historian may be one of the last people to document a fading or endangered culture, language, or set of traditions, thereby playing a crucial role in its preservation rather than its destruction.

Reference 

1. Gemini assistance 

2. Conceptualization from Breaking India 2.0 by Rajeev Malhotra