cases of repressed memory of abuse do occur and are legitimate.

No, they don't and they aren't. There has never been a proven case of a "repressed memory" that couldn't be described as simple forgetting. Experimental (not clinical) psychologists have done scads of work on memory, largely because of the haywire "repressed memory/satanic witch cult-daycare" hysteria of the 80s.

One of the surprising developments in the study of memory is that many people completely forget key details or even the entire occurrence of major life events, negative OR positive -- including things we would reasonably expect people never to forget (these include things like violent assaults, car accidents, but also winning a major prize or scoring a winning point in a game). People completely forgot these things happening to them -- and on the flip side, it's amazingly easy to induce people to believe that things happened to them that didn't. And sorting out the truth is often impossible unless there's a third party involved who was a witness--and assuming the witness's memory is reliable, which is a toss-up as even people present at the same event will report entirely different accounts of it.

Here's a simple and rather silly example from my own experience: Once my mother and I were talking about the movie "Raging Bull," and I mentioned I had seen it with an ex-bf of mine. She countered, "No, you didn't, we saw it together," and proceeded to name the theater, state the time of year, and describe what I was wearing that day. She'll repeat this any time the subject comes up. I, however, will go to my grave swearing that I saw the movie in an entirely different city with an entirely different person. Is one of us lying? No. We're both sure we're right, but one of us clearly isn't.

This will be the first time a Massachusetts court fully considers the scientific, evidentiary basis for repressed memory. The Commonwealth is behind the curve. Since 1998 state courts have been dismissing repressed memory as junk science, and prosecutions based on it have become rare. In 2007 an Indiana court rejected Dr. Brown's testimony as misleading, and a federal judge threw out a $1.75 million verdict in a case that hinged on Brown's expertise. In a 2006 amicus brief, dozens of pre-eminent social science researchers stated, "Decades of research and scientific debate have clarified over and over again that the notion of traumatic events being somehow 'repressed' and later accurately recovered is one of the most pernicious bits of folklore ever to infect psychology and psychiatry."

http://www.thenation.com/doc/20090316/wypijewski

Elizabeth Loftus is one of the most respected researchers in the field of memory, especially childhood memory--this is an article from the height of the repressed memory craze:

The whole decade was somewhat crazy. The excellent PBS Frontline show, The Child Terror, documents the insanity of the time. Examples of the sorts of things that could happen to perfectly innocent people were on display in the first McMartin trial, and also in what some now call The Amirault Tragedy.

My point in linking to these things is to posit what possible reason an innocent man might have for entering a plea of nolo contendre. It seems possible to me that given the hysteria of the time and also the massive amounts of money that it takes to put on an effective defense, accepting the consequences of a nolo plea without actually admitting guilt might have been the only option and may well have been the advice of counsel. The last thing defense counsel wants is for to have children in front of a jury describing sexual and/or physical abuse at the hands of a parent, especially during that period of time in our history.

Some of what went on in the 80's with respect to "The Child Terror" were just plain hysteria and perhaps reminiscent in some ways of witch trials.