More context is needed! It could mean anything!!!!!

Please provide the sentence for a more complete explanation.

"Shit" can be a crude way to refer to things or stuff. Therefore, you can say: "look at that red shit over there" to refer to something that is red in color that is unknown to you or that is a real mess and it's red. "Look at that shit", this means look at that mess or something that is distasteful to the speaker. This is a very common, albeit crude way to talk.

Communists maybe? We definitely need the context.

Red shirt? As in Star Trek? Otherwise, I'm thinking of blood in the stool, but I've never heard of "red shit" as a phrase