What I've found is that people come to it in a state worse than ignorance: they think they know, but it's almost entirely wrong.
But it is possible, as a reasonably intelligent non-scientist, to follow the research and learn enough to have a decent understanding about what's going on.
In AJ Jacobs' case, most of his matches are going to be much further back than it seems because Ashkenazis are an endogamous population (inbred). So are French Canadians, Mennonites, Amish, small island populations, etc. This is why he has so many matches. Most are probably estimated as "3rd-distant cousin", although the designation would more realistically be something like 6th-10th cousin, and without proper record keeping (which there isn't for Ashkenazis) there is absolutely no way to ever find the common ancestor. So he can call them all cousin, but he can't prove it despite the DNA segment matches.