One of the difficulties of doing genealogical research has nothing to do with the research or finding sources, it has to do with what you find. This was brought home to me again yesterday when I taught at a local African-American Genealogy Conference. One of people I talked to yesterday, who you would never consider to be Black, related how he had discovered three black ancestors. On the other end of the spectrum, one of the discussions in conference centered around finding out that your Black ancestors were really Puerto Rican, European or Asian. The laws in England changed. Early laws provided that the offspring of a White father and a Black slave mother were free-born. Later, the law flipped over so that if the mother was black the children were still born slaves. But then there were White female indentured servants who had offspring with a Black men, so their children were free-born.
But the difficulty is finding that your ancestry was not exactly as homogenous as you might have been led to believe. Inter-racial marriage is only one of the cultural and social issues that researchers might have to struggle with. In doing some clean up of names in my own ancestry, I found one name recorded as "Marinus Adopted Christensen." There is nothing I have found so far to indicate how this ancestor might have been considered adopted. Speculation, on my part, indicates that he might have been born to one of the daughters in the family, out-of-wedlock, but the family record is silent. The stigma of an out-of-wedlock birth was too great and the family did not "talk" about the issue except to mark the ancestor as other than part of the family.
Sometimes the discovering the family roots turns out to be divisive rather than a joyful family event. Discovering that an ancestor was abusive, a criminal or insane isn't always an acceptable topic at family gatherings. The combined family memories can be so painful that raising the subject will effectively end your participation with the family. As a researcher, you may even be considered a traitor to the family.
Finding out that your ancestors were human is an occupational hazard of doing genealogy. In my own cultural and social heritage, polygamy is a big issue. I have previously related how the subject was not open for discussion in our family. The issue today has become a rallying cry for those who would disparage descendants of polygamous families because of their religious beliefs. Rather than confront the issue as a historical fact and leave it at that, I personally have been treated as if I inherited a social disease merely because of the practices and beliefs of my ancestors.
One of the major difficulties of encountering such an issue is the "wall of silence" surrounding the events and facts. At the time, the family members may have shunned and alienated not just the offending person, but all of the members of his or her family. In my opinion, many of the "disappearing" relatives didn't disappear at all, they were merely dropped from the family because of who they were or what they did. We recently had a situation I became aware of, where a younger member of a distantly related family wanted to marry "outside" the acceptable standards of the parents. The parents' reaction was swift and severe, totally cutting the person off from all participation in the family and acting as though the person were "dead." You see this in movies and read about it in books, but guess what? It happens in real life.
What do you do when you find these anomalies? Keep doing your research. I suppose you could adopt your family's prejudices and attitudes, I find that all the time also, but you will only end up passing the issue on down another generation. How about adapting to the idea that insanity, mental unbalance, criminal acts and other problems are a fact of life. Get on with your research and if your family doesn't want to hear about it, don't discuss it with them. Let the next generation try to resolve the difficulty, but leave the next generation the information necessary to do so.