Certainly the law is simply a stupid thing, it inserts itself into a space in case management it does not belong. That the legislature believes it can micromanage every incident is fool hardy. The broken nose didn't help. The law is to serve a cosmetic purpose, to relieve folks from such incidents of the encumbrance of ever being considered or treated like suspects. It seems to forcibly deny authorities the opportunity to treat individual cases ... individually.
It was an over-reach. It shows a blatant distrust in law enforcement and the legal process. If law enforcement and the legal process has problems it seems the legislative solution must be something other than to insert itself into that phase of incident resolution. Curiously, it seems that better staffing of the public defenders office would be a start, falsely suspected or accused 'stand your ground' folks would likely see more rapid remedy and release. I suspect that the same folks who passed this hold the public defenders office in complete disdain where it is in swift competent representation where an incident such as this can be processed smoothly while maintaining the rights of the kid, the gun-man, etc.
Police need to operate with at least some level of suspicion of guilt, they have dead people at their feet, it is a different phase, post crime scene processing where presumption of innocence, cause, and due process ensue.
What is unfortunate is the act of arrest itself is such a blemish. Indeed there are employment things that ask not only have you been convicted, but have you been arrested. That screws things up a fair bit a precipitates laws like this.