I should say that homicide and suicide by gun are causes of death #2 and #3 for that age group (the order of the two is different between 15–25 vs. 25–35 year olds). Successful suicide rate is notably higher in places chock full of guns.
Which is not even to mention the daily occurrence in the USA of young children accidentally shooting other children (typically siblings or friends) or themselves to death.
Having a gun in your house is one of the biggest possible risks you can bring to your own life and the lives of people in your family.
We're talking about forms of death over which the deceased have little control. Fear of airplanes, nuclear accidents, etc, etc.
For the purposes of comparing evaluating people's fear of things that could kill them that they don't have control over suicides (60% +/- some depending on which party's sand you bury your head in) and intentional non-criminal (defensive) gun deaths should not be counted because they are not something people do not have complete control over. Don't try to kill yourself and don't try and commit a crime against someone who's armed and you have basically nothing to worry about.
People are afraid of gun accidents in the same manner in which they are afraid of other forms accidents that they have some degree of control over (like car accidents). They take steps to reduce their likelihood and encourage (through various means) others to do the same (i.e. social disapproval of people who do unnecessarily dangerous things).
For the purposes of discussing public perception of the risks of nuclear power "gun deaths" as a lump sum is not useful and the effort to pick it apart and analyze the components is not worth the risk of derailing any useful discussion with politics.
Which is not even to mention the daily occurrence in the USA of young children accidentally shooting other children (typically siblings or friends) or themselves to death.
Having a gun in your house is one of the biggest possible risks you can bring to your own life and the lives of people in your family.