This is why you pay a lawyer to make the awful choices for you. It's a tactic, not a moral decision on the lawyer's part, done as part of a vigorous defense.
Frankly, unless you're sure you're going to lose a case big, or can't afford a lawyer for a trial, there's a good chance the state may screw up.... or you pull the "he beat me on Superbowl Sunday" defense and find the one sympathetic juror.... or the state won't want the time and cost of a full trial and deal it out...it's a ploy. Look at what's gone on with the John Gotti Jr trials in New York--the second one is now thrown out. Why would he ever plead guilty?
The more a case plays out on TV the more it strengthens one side at the cost of the other side. There are consultants who get paid to measure the attention and direction of the public opinion and how it'll affect jury selections and prosecution strategies on cases like the one you mention. The DA's office gets rated on convictions, and it'll weigh the costs of a big trial with lots of media coverage that may play against the prosecution and weaken the case, versus dealing out a lesser plea with a sure conviction.
It may stink, but that's the way it is.
(edited for clarity!)
