It seems that, increasingly, law enforcement is viewed as an occupation that requires nothing more than a uniform and a gun. As such, many people assume that they know better than that uniformed person. Every profession has some people who make mistakes, but I think it's a mistake to assume that law enforcement persons, in general, lack reasons for their decisions.
The public may be curious about how someone died, what their last minutes were like, and so forth, but the family has the right to ensure that those details are withheld if the death is suicide. If the death is murder, withholding those details greatly improves the probability of a successful prosecution, and the public release and debate of those details can seriously impair a prosecution (case in point: OJ Simpson, the child murderer in Florida).
Releasing details about a suspect can impair the ability of law enforcement to successfully gather more evidence. Joran van der Sloot is a good example of this. Media interference in the police investigation gave the suspect the upper hand, and he was never prosecuted for the murder that he committed.