Ninja seems straight-up annoyed that Donald Trump would even hint video games are the problem when it comes to gun violence in America ... telling TMZ Sports that's just a ridiculous claim.

"Violence, it's not video games," the Fortnite legend says ... "It's just how it is, man."

Of course, No. 45 would strongly disagree ... after the tragic mass shootings in both Dayton, Ohio and El Paso, Texas this month, Trump said, "We must stop the glorification of violence in our society."

"This includes the gruesome and grisly video games that are now commonplace."

28-year-old Ninja -- real name Tyler Blevins -- is one of the most famous gamers on the planet ... reeling in millions of viewers and even more dollars for playing in the virtual world.

And, when he was leaving Catch earlier this week, he let us know he thinks Trump's just flat-out wrong.

"Come on, man. Have you seen Minecraft? What's violent about Minecraft, bro? Nothing, man."