We all know that charts and graphs often are designed poorly, so simply look at the facts: Of the 77 countries listed on the Wikipedia link in your article, The US is the 10th highest in gun related deaths @ 11.96 per 100,000 (behind crime infested countries Honduras, Venezuela, San Salvador, Swaziland, Guatemala, Jamaica, Brazil, Columbia & Panama).
If ameliorating gun proliferation is your “solution,” then statistics from other countries literally do not matter. We go into why here:
The Magic Gun Evaporation Fairy
Three Reasons Why Gun Ownership Rates From Other Countries Don’t Matter
Suicides by gun are part of the equation and cannot be discounted simply because you don’t like them included — they are the result of the use of a gun to cause a death, and in that category The US leads ALL 77 countries with a suicide death rate using a gun of 7.10 per 100,000.
Guns are definitely a convenient way to commit suicide, but calling our gun suicide problem a “gun problem” and pretending that South Korea’s suicide rate (largely by other methods) is totally fine and not worth considering is presenting a false counterfactual. In fact, SK’s suicide rate alone is larger than the US’s combined homicide and suicide rate, by all methods, gun or no gun.
We go into suicide in depth here: