Genealogists tend to be an older crowd for sure, for a mix of reasons. I'm just entering middle age, so I can only speak for myself. I remember as a very small boy doing an elementary school family history project and finding it captivating. There were people I had never met but played an important role in determining who I was and the family culture I grew up in. To me, that is just inherently fascinating, and I have a hard time understanding people who don't feel that way (even though almost no one I know shares this passion, including my closest friends and family members). I think most genealogists have a similar experience. We end up finding 4th cousins who we are are very tangentially related to, but we bond over our shared interest in our ancestors and the process of genealogy research.

For me, genealogy is almost a perfect fit for my skills and interests: I believe strongly in the importance of family, I enjoy history and geography, I am trained as a lawyer so I can decipher the many legal documents that lead to important details, I enjoy the detective work involved in cracking hard cases, I enjoy the sense of completion of filling in a new branch on the tree, I enjoy writing and sharing my research with family members, I'm a skeptical person and have good critical reasoning skills, so I can spot a lot of errors in other people's research and try to correct them. Perhaps most of all, I enjoy learning about the lives of my ancestors. I feel that telling their story honors them and keeps their memory alive, and that's important to me. I hope some day my descendants will enjoy reading my work.

There are some people who get the bug for genealogy and get really into it, and maybe that helps explain why.