How often are guns used this way?
Often.
Most people killed by guns are killed in their own homes. Either through suicide or family disputes that turn violent.
Other countries have lower gun deaths because most people can't buy guns. Its hard to access guns and the types you can get are more limited.
In America freedom also means freedom to murder as many people as you can before going out in cuffs or a body bag. To prevent people from doing that is an apparent infringement on their rights here. So until there is a federal law on the books, reinforced by the Supreme Court, you'll still keep seeing this shyt.
The gun debate was over when the leaders of this country decided that grade schoolers being murdered is collateral damage and worth it for the right to kill whoever upsets you for any reason or no reason at all.