Ron White is scoffing at criticism Stephen Colbert hurled a homophobic slur Donald Trump's way ... saying he has carte blanche to say whatever the hell he wants. 

Ron was heading to lunch Tuesday at Wolfgang's Steakhouse in Bev Hills when we asked him about Colbert's jab at Trump, "The only thing your mouth is good for is being Vladimir Putin's c**k holster."

Ron hadn't seen the footage, but he jumped to Stephen's defense, insisting the comments were all made in the line of duty.