I did think about Marxism, but why would it be less likely to explode in my face? It's also a modern political position.

The probability of a staunch Marxist commenting on this blog seems to be vastly less than the probability of a staunch (non-religious) Republican doing so. We don't want to drive away many potential readers on account of their surface positions before they have a chance to reconsider things. Also, we really don't want an accidental political flamewar to start in a comment thread, so political examples should be chosen to tread on fewer current toes if at all possible.

Would you prefer that next time I include two examples, one attacking either "side" of the political "spectrum" next time?

No! This would make it even more likely to cause one of the bad outcomes above! This isn't about "fairness", it's about prudence.

Or can you think of some historical example that would be as immediately recognizable to everyone here as the Republican one?

Again, I think people here generally have the basic political literacy to recognize the Marxist example.