Casey Anthony was indicted by a Grand Jury, not charged by the prosecutor.
WHO brought the charges before the Grand Jury? Prosecutors can manipulate case data to secure charges.
The prosecutor had to take the case before the Grand Jury and request an indictment.
As Mario Ouomo famously quipped, "A grand Jury would indict a ham sandwich if the prosecutor told them to do it."
The bottom line is that none of us "Wednesday morning, arm-chair jurors" have sat through the weeks of testimony like the jury did, where they heard the testimony and saw the demeoner of witnesses and the physical evidence while sequestered from the tabloids and cable news pundits. "Proof beyond a reasonable doubt" is a very high standard that requires near certainty.