It's 1992's INVADER. It's about an alien that invades a military base and transforms, by the end, into a Voltron-like robot. The robot says, ""I love America! I want to f**k America!"
You might be onto something here, and I'm embarrassed because I've even reviewed it and interviewed the director. I think that "Invader" didn't come to mind because it is a huge robot. The ASMODs robot does sit on a pile of weapons and spout a lot of patriotic phrases, and he does use the F-word at least once. Here's the review:http://www.badmovies.org/movies/invader/
And a screenshot of the robot in the film: