Yes, "about these pressing moral issues!" screams sarcasm, but I don't see how the original quote assumes that people in the USA somehow believe they have a unique claim to being less wrong, which would make the most sense as a target of the sarcasm. The quote isn't saying that unlike our smartest ancestors, we do have all the answers, only that we're less wrong (and should suspect that there's probably much that we're still over-confidently wrong about), and isn't saying that we is any particular nationality (nor is any strongly implied).