Typically, you're eligible to use that title after receiving the degree. I know a number of non-practicing people who have degrees and sometimes (rarely, really) use the Dr. It's still a term of respect for completing a demanding program.
Of course, with Wakefield it's difficult to still muster such respect.
"Dr. Andrew Wakefield should be in prison for fraud. Why isn't he?"
Probably for the same reason Saddam didn't get a real trial. In addition to having dozens of high-profile collaborators, including the heads of several medical schools, the kinds of practices he engaged in aren't even that unusual for medical studies. Even if Wakefield could be convicted of criminal wrongdoing, which may well be possible, there is no one in pharma or the medical world who benefits from a highly-publicized show trial.
What's actually more interesting that the Bill Gates thing is the fact that Salon.com just retracted their 2005 RFK, Jr. article because it was apparently finally debunked in Seth Mnookin's new book:
Amongst other things: found guilty of serious professional misconduct; diverted £25,000 of lab budget without telling his superiors where it was going; did invasive procedures on children when (a) his contract at the hospital explicitly said he could not treat patients, and (b) he was not trained for pediatrics.
It doesn't however mention the "fraud" word (it calls him "dishonest" and "irresponsible" instead), but this is hardly the behaviour of a reputable scientist.
