The Thing seems like it would have been a little early to be making any commentary on the AIDS crisis in 1982. I think John Carpenter would have fessed up to such a thing by now. It's no secret what "They Live" is all about.

The blood test scene is in the original novella, which was written in 1938.

The POTA films don't take a heck of a lot from the original novel, aside from Apes subjugating humans, and IIRC, doesn't even take place on Earth. The second movie does seem to be commenting on the peace vs. war issues of the 60's. The fourth one could be a allegory for the racial tensions of the era.

Such analysis has merit, but in the case of The Shining, it's gone into very strange territory. I doubt even Kubrick thought of running two prints in opposite directions projected as one image to conceal hidden meanings.