RIP to the victim
People here seems to ignore two thingss.
Muslim Extremistism, or what you called "Brown Terrorist" is no where near the number of terrorist incident report by the FBI per decade.
Have you heard of Cesar Sayoc? He is a Hispanic Anarchist terrorist which mailed 11 pipe bomb to federal and political office last week, chances are you probably never even heard of him unless you follow US local news.
Or name like Jerry and Joseph Kane, Joe Stack and so on, you probably don't know all these people but they are all afflicated to domestic terrorism. Just that becuase they didn't kill many people, you probably never heard of them internationally.
Muslim Terroristism is on the rise, but still no where near the level of Domestic Terrorist group such as Anarchist movement and anti-government movement.
Second thing I want to say is that the right to bear arms is not an issue here, many country allowed what US allowed in term of procession of weapon, many more country have a even lax law than the US, but you don't see them (Canada, Sweden, Norway, France, Netherland) having mass shooting event like America.
The underlying problem with this is the people, not the guns, you can take away the guns and as long as these people and their grievance and their problem are not going away, you will still have Mass Casualty Event
Focus on the people, not the gun.
I got to read a report few years ago, who explained US drastic shift to "Islam related Terrorism" in the past 2 decades, whatever in Manpower or/And Budget, That drained the "Minds"/"Assets" etc... from the good old US Terros services.
That report spoke about the resurgence of those same local Terro groups, who took that shift as an opportunity to regroup/Adapt their Ideology and get Positive "Public" perception.
They compared them with ISIS 's "Traversée du Desert" and their resurgence phase.
The Conclusion highlights the same problems that was facing the US/Europe services with ISIS take over in SY/IQ and those groups. Where reorganization of those past US Security Services will take almost a Decade if Everything goes as planned.
As for your "Arm bearing" Opinion, I may give a Different opinion. Having no guns, will decrease drastically the number of causalities. Drastically Tightening the access to bear a gun will Decrease the probability to end up in the wrong hands.
Yes, The work should be focused on People But the problem is not with the sane one, who will not act... or not have a gun but the minority pool who could get pass the net. It's almost impossible with the available manpower/budget to check individually every citizen who wish to get a permit, many are prone to act in certain situation in their life while never been involved in an event that will require them to get redirected to X or Y medical/Psychological services and therefore not being put in that " Black List".
And Last. The causalities involved with a Rifle is Different from a Gun who is also Different from a Knife. If you can't stop X or Y individual to act, you can decrease the casualities.
As for your Examples, like Sweden/Norway/France etc... Most of them banned Rifle ownership and a HandGun/Carabine permit is extremely difficult to get, You also have multiple checkups/Formations/Training as long as you've got your permit. But ofc it isn't perfect, But I think it's working according to the "almost" non existent event involving "Legal" Arms.
The US, shall change her Gun Laws, their is no debate about it... If ofc they want things to change. But it's a Difficult task, since it isn't just a "Lobby" thing or a Political conspiracy... But US citizen themselves, even those who do not have arms see that Guns transcend Laws and therefore put it into the "Cultural" Realm. And as every Way of Life... You can't impose a Drastic view, neither a Complete removal in a short period of Time.
