Add all of the countries in Europe together to get an equal population to the USA and you will see that the homicide rate is higher than it is in the US. Or put another way, take all of the 50 States, and separate them. You will find that the overwhelming majority of those States are less violent than the countries in Europe. You will also find that the most violent States are those with a high illegal alien population, and in Democrat controlled cities. Chicago the city, has a higher homicide rate by itself than all of the Western States combined if You leave The coastal communities of California out. And they are Democrat controlled.
Adding populations together doesn't affect the rate.
Besides, when you add the populations of those European countries together, the rate for gun homicides in the US is more than 20x higher than in Europe at 0.17. The population is 100 million higher than in the US.