I'm working on approaching this differently. Just calling someone retarded is ineffective and does nothing to help others who see the exchange. It's just more noise and shit in an already noisy and shitty environment.
Discussion
I've been explaining that what we have isn't capitalism and why. Of course 5 minutes talking to me does nothing compared to the hours of daily propaganda they consume, so they are always back on their bullshit next time I see them.
I've had this same experience for the most part. I recently decided to stop wasting my time on anyone who isnt willing to prove they've done a basic level of education relevant to the topic. I'm still developing that standard and test, but I also do it with Bitcoin. It's saved me time. If people can't tell me what inflation is, we're done. If they can't go research the links I send them then why the fuck waste my own time?