I'd expect that the boring reality is that it's trained on highly ethos/logos text (academic works) and thus always presents itself as such, even when its weights cause an invalid assertion.
For example, there was a voice actor that lied about being paid a pitiful sum of money for a gig. Everyone took her side initially (as one should _if_ it were true) but the people saying "well, this just seems odd" were being more or less attacked and told their opinions were awful.
The quality of discussions I have on HN and niche forums are 100x better than reddit.
Honestly feels like they're both pretty important datasets to ingest if trying to build a model on human speech, I reckon social medias, comment sections and co have the most natural human conversational text online.
Their training objective, which is to predict the next piece of text in their training data, does not incentivise them to respond that they don't know something, as there no relation in the training data between the AI not knowing something and the correct next text being "I don't know" or similar