Donald Trump's rant about the "wonderful" Hannibal Lecter isn't sitting well with one of the guys who helped make "The Silence of the Lambs," and he's taking a bite out of DT's rhetoric.

Edward Saxon -- part of the Oscar-winning trio that produced the film -- tells TMZ ... he has a pretty good idea why Trump might be so eager to split some fava beans and a nice Chianti with old Hannibal the Cannibal.

He says, "My guess is, Letcer feels like a kindred spirit. Part of it may be aspirational in that Lecter is brilliant and is able to see into people’s motivations and control them."

Saxon adds, jokingly, "It may be aspirational on a culinary level as well, you know, to have more elevated gastronomic tastes" -- a pretty clear shot at the former president's love of fast food.

Of course, on a much more serious note, he says he doesn't like the idea of Trump comparing immigrants coming into the U.S. to the murderous Lecter ... telling us it's abhorrent to liken one to the other, which Trump boldly did during a weekend rally in New Jersey.

As we reported ... Trump referred to Anthony Hopkins' character as the "late, great Hannibal Lecter" -- remembering him as a great guy ... and in the same vein, using him as a way to describe the types of people that are pouring into the country ... namely, evil cannibal types.

Saxon says that while fictional Lecter might be an "alluring role model" for Trump ... it's still not cool to make the juxtaposition -- and while he isn't surprised, he says DT just shouldn't go there.

He says ... "Comparing people who are looking for a better life in America, like my grandparents did, to a serial killer, is just wrong."