Yeah, of all the sites to not buy, the one with your own name and the .com is probably the cardinal sin of political campaigns in this day and age.
If someone had owned it, Jeb could have had gone to what is known as the UDRP, an organization that sorts out accusations of cybersquatting (which is what the process of buying a domain with someone else's name is) and fought to get the domain back. I mean, it's not like Jeb Bush is a common name and that anyone else uses it; it's a pretty clear case of cybersquatting and the UDRP would almost certainly award the domain back to Bush.
Now, a lot of times, they let somebody who is using the domain for something related to that person to keep the domain, but since it's been since 1997, it's pretty clear that the original buyer was speculating on that domain.
In short, Jeb's an idiot for not challenging this.