Anyone who has seen Leni Riefenstahl's "Triumph Des Willens" (Triumph of the Will), the documentary about the Nuremburg Rallies, understands that even the vilest propaganda can attain the status of great art. Without a doubt, Nazism was a force to be despised and resisted, yet "Triumph" remains a fascinating, even great film.
That said, I will not put "Red Dawn" on the same plane as Riefenstahl's work. It is neither as good a film nor as vile propaganda. But it does underscore a point I see running through many of the criticisms of "Red Dawn" that have been posted here. Many of the movie's detractors reject the film out of hand because of its undeniably conservative overtones. This, I believe, is lazy criticism. The movie has an excellent pedigree. I suggest you search on ImDb under John Milius' name to see what other films he has been involved in. Some of his more notable accomplishments include the screenplays of "Jeremiah Johnson" and co-authoring "Apocalypse Now", as well as the notably UNconservative adaptation of "Clear and Present Danger". Basil Poledouris' score is fantastic, with its Copland-esque homages. The touches of authenticity in the film are also admirable, including the indoctrination camp (see the recently published "Gulag" or Koestler's "Darkness at Noon")and "Radio Free America" scenes, not to mention the efforts the filmmakers went to to make the military hardware look Russian (as opposed to Russians flying American aircraft in dismal movies like "Iron Eagle II" and "Rambo"). Yes, Red Dawn is propaganda, but just because it may be, from your perspective, the wrong kind of propaganda, you are not justified in invalidating the whole enterprise. It is slick, well-made, and memorable.