The risk of today's genetic genealogy tests is that they tend to divide people into groups, whereas the real message that emerges from genealogy is one of connections. For centuries, scientists have tried to sort people into biological categories. In the 18th and 19th centuries, they pounced on the idea of race and used it to formulate hypotheses about human differences that had disastrous social consequences. In the 20th century, scientists began to explore the greater complexities of our biological histories, which are impossible to capture in a word as simple-minded as "race." If genetic genealogy tests explored and explained these complexities, I'd have no problem with them. But most of today's tests hark back to the bad old days of racial science.
People may like to think that they're descended from some ancient group while other people are not. But human ancestry doesn't work that way, since we all share the same ancestors just a few millenniums ago. As that idea becomes more widely accepted, arguments over who's descended from Jesus won't result in lawsuits. And maybe, just maybe, people will have one less reason to feel animosity toward other branches of the human family.