At the same time many Americans don’t quite believe non-Americans are proper humans. See how they justify invading other countries. Or how any comment critical of US gets flagged as “Chinese comment farm”.
I think it's the broad, off-topic, pro-China/anti-US comments, like this that make people feel like it's probably a bot or human equivalent.
If the post was actually a reply or rebuttal to any of the comments content it probably would give that vibe.