This argument is disputable on empirical grounds. It is even more disputable on theological grounds. Every argument favoring gun control represents a skewed harmartiology. This notion is too inane to consider. But more complex samples of the same line of reasoning ensnare even ordinarily thoughtful people.
People do because they are sinners.
So something besides man must be imputed the culprit. But the fact that enterprising people, not the least being the ubiquitously benevolent civil government, would devise some new, perhaps more lethal weapons, indicates that elimination of guns does not guarantee the elimination of the problems gun control supposedly solves. Eliminating guns won't solve that problem. But gun control never means gun elimination. Proponents of gun control usually do not advocate depriving police officers and military personnel of guns, although it is not clear that police officers and military personnel do not misuse guns.