It doesn't matter how many injuries come from things that are nothing to do with guns. If gun ownership were more tightly controlled, those 14000-19000 nonfatal injuries and the hundreds of fatal injuries from accidental shootings would be reduced by at least an order of magnitude - lives would be saved. You might as well say that, as deaths due to Non-Hodgkin Lymphoma are around 18000 a year in the USA, then it is not worth attempting to find cures for this disease as so many other things are likely to kill you.
Here in the civilised world, where gun worship of the kind practised in the USA is considered an aberration, murder rates and prison populations are proportionally tiny compared to the USA. Honestly, most developed countries think you are all nuts.