I know you're just repeating what you've heard, but I have to tell you that's an outrageously stupid argument they make.
That's basically saying: criminals don't obey the law, therefore laws are pointless.
And yet we know that's absurd, and all modern civilized societies rest on a pillar of the idea of laws and enforcement and a justice system that shape and constrain societal behavior. Why do I even need to type that? Seems too obvious.
We also have examples of nations that have few guns, and correspondingly few gun crimes, so we have both reasoning that backs it, and real life examples. This is not some big mystery.
The only reason we have pervasive guns in the U.S.:
2nd amendment
the gun lobby has been effective at convincing people to support them and broaden the interpretation of the 2nd amendment, and fight any/all gun control.
It's now a gun culture, backed by constitutional interpretation, and a powerful gun lobby. We have Trump in office though, so the idea we'll see half the nation get wise to all this and make some good choices, I'm not holding my breath any time soon. Gonna be along time if ever.