Let's face it. The truth can be painful. Is it our job to rewrite history to reflect our present politically correct and socially bland interpretation? The history of the United States is not all sweetness and light. Likewise, our ancestors did things we may not be proud of, but does that give us the right to withhold historical documents based on our personal criteria for "privacy" and "sensitivity?" In some cases, these issues are life threatening.
There are extreme examples of the use of "genealogy" in a way to promote terrible and evil goals. Prior to World War II, in Germany, the census was used to collect data on Germans and then specifically on Jews and other minorities. The initial reason given for the state's desire to track racial groups was to preserve national security. Later, this same information was used to attempt to eradicate these same ethnic and racial groups. For a chilling chronicle of this horrific use of a census see the following:
Aly, Götz, Karl Heinz Roth, Edwin Black, and Assenka Oksiloff. The Nazi Census: Identification and Control in the Third Reich. Philadelphia: Temple University Press, 2004. (Originally, Die restlose Erfassung : Volkszählen, Identifizieren, Aussondern im Nationalsozialismus).
With this type of background, there are those whose reticence about publicizing information about their ancestors is a well-based concern. There are still ethnic and religious minorities that are being actively persecuted. I am personally well acquainted with being the object of religious persecution, in my early years, during my service in the U.S. Army, and from time to time during my schooling and career. I also am a descendant of ancestors who were the object of a government sponsored extermination order.
In the United States, we have a past history of slavery with its inheritance of racial prejudice and tension. Genealogy and its handmaiden, DNA testing, is upsetting a lot of re-written history by demonstrating that some of our traditional "white" families are, in fact, descendants of slaves. But much of the sensitivity expressed by researchers deals with more mundane and even petty issues. How many times, when confronting such an issue, have we wished that the people involved had been more forthcoming in their records? Those who take refuge in "royal" lines are not immune to finding out embarrassing facts about their ancestors. No extended family is immune from infidelity, insanity and criminality.
Many inherited diseases were considered to be "unmentionable." Because we are heirs to these "privacy" or "only family" matters, we may be at risk for any number of genetic disorders, including mental illness, and have no clear information to determine the severity of the problem. An ancestor that seemed to act in an erratic or even suicidal manner, could have been the victim of extreme abuse, but this is a tabu subject for family history and discussion.
Genealogists tread a fine line between rewriting their own history and preserving the historical record intact. I fall far on the side of historical preservation. I have my own set of ancestral mysteries, some of which I have resolved and some I likely never will. If you choose to withhold information from your family and your own descendants, make sure what you are doing is not an attempt to re-write history. If you choose not to put your "sensitive" information online, at least make sure that it will not be lost to subsequent generations who may inherit their own ancestral mysteries.
As a parting note, a question. What is the most challenged and banned book in the United States during the ten years from 2000 to 2009? The answer is the Harry Potter series and number fourteen on the list is Mark Twain's The Adventures of Huckleberry Finn.