Who said anything about the number of guns? The link I provided to wikipedia was homicide rates per 100 000 people.
And of those countries with higher homicide rates than the US how many have more restrictive gun laws than the US?
Virtually all of them. Mexico has restrictive gun laws and only one official gun source, very low gun ownership, and a vastly higher murder rate. Cuba's gun restrictions can be imagined. For most of these countries, the government's policy and that of the ruling class has been "For gods sakes, don't arm the peasants."
In the UK, after they tightly restricted firearms, their crime rate skyrocketed. Austria greatly increased firearm restictions after a school massacre, and they got another school massacre.
The world homicide rates vary by a factor of about a hundred, virtually independent of gun laws or firearm prevlance. Switzerland has a fantastically low homicide rate and everyone has assault rifles, even teens, often fully automatic. The US military has a very low homicide rate yet includes large numbers of male teens with machine guns. And of course, the most violent US cities generally don't allow most civilians to possess a gun.
Other factors are at work, and of course the world's violent death rate was vastly higher before guns were even invented.