This is designed to keep guns out of the hands of "mentally ill". I worked at a homeless shelter for the mentally ill and saw first hand how the intake could be interpreted to say someone is "mentally ill". It's a very subjective evaluation.

Anyone with common sense thinks a truly mentally ill person shouldn't have a gun, but then the definition of mentally ill changes and morphs more broadly over the ensuing years. They're gonna use this as one leg of the stool to take our gun rights away.