'Che' does not mean communist
In Argentina, people often say "che" to one another. The first time someone did this to me, it threw me for a loop. Were they making fun of me? Implying that I was a communist? Eventually, I figured out that it's just a way of saying "hey" or "yo" or is sometimes a term of endearment. So don't worry, if someone uses this term, it doesn't mean they think you're a pinko commie--it means they like you. Although, this being Argentina, they might like you even more if you are a pinko commie.