(Or are the prosecutors not versed well enough in the law to know which law/crime is the correct one that was violated?)
What do you think about this: if the prosecutor thinks the big charge might not stick because the evidence is questionable then charge the lesser crime?
Or perhaps (I know many don't like this, especially the government) a separate trial for each charge. Yes, the cost to prosecute goes up (if all charges are going to be charged) and that's why they combine multiple charges into one trial. But psychologically, if the jury see that a person has been charged with 13 crimes then he must be guilty of one or some of them right? If the state had to try each charge separately and the big one didn't stick, then if the state truly thought the next one would stick do that trial.
Our legal/justice system has a flaw and that flaw was to let a few guilty men go free to safe guard and protect innocent men from going to prison.