Except the big call in the US is to ban the AR-15, not any handguns, or any bolt action rifles, or any shotguns.
IMO two things significantly influence pressure to ban things, the utility they possess and the risk they pose. You may be correct that AR-15s may present little risk (though I'm not familiar enough with model-specific gun deaths and injuries to know whether they are low risk) but somehow the perceived risk is high.
The other factor, utility, may be coming into effect with calls to ban AR15s, they are simply deemed unnecessary by those calling to ban them. They seem to be overkill for a hunting weapon and unwieldy for a personal protection weapon, they represent low-hanging fruit.
The big call in the US is to ban guns that are rarely used in crimes.
From this distance, I'm not sure where the big call is. There seems to be a vocal minority in favour of significant restrictions on handgun ownership but then again that seems to be a hot-button issues for second amendment supporters and any attempt to significantly restrict handgun ownership is simply dead in the water due to the support that the NRA manage to get.
Most burglars in the US are unarmed. Most states in the US do not allow you to kill a burglar over property alone.
But there is a clear perception of risk among people like my brother-in-law that his house is likely be stormed by multiple armed people at any time and that he and his family are permanently at risk of being attacked. This despite living and working in a nice upscale Denver suburb where, according to the local newspapers, violent crime is an exceptional occurrence which attracts lots of column inches of coverage.
Even if these two victims had been burglars, the charges would be the same, imo. The shooter had no justification to shoot burglars at a shed far away from his house.
As I've said, in this case the shooter's motives aren't clear, there is suspicion that the decision to shoot was motivated by a desire to kill two people who had bought "his" land rather than fear of an intruder.
More generally however we have people who are sufficiently frightened of armed intruders to open fire on their own family, neighbours or strangers seeking help. They too may have had no justification but fear and the ability and desire to protect themselves with deadly force led to unnecessary deaths.
Here in the UK people may be just as frightened (though I suspect on average they are not but have no figures to back this up) but because we are more prepared for the Police to maintain our safety and we are much less likely to have a firearm accessible (the few we have tend to be securely stored) then we are less likely to shoot, with tragic consequences - and yet are no more at risk from the dreaded armed marauders.