I defer to hubris in most of these cases.

I am guessing that the people who made the decision to train on Reddit had no idea what type of place Reddit actually was just a short time ago. Maybe they heard of Reddit, maybe they noticed how useful Reddit was in search results, maybe they browsed Reddit and only saw the facade; what they definitely didn’t do is be a Redditor for years.

Any Redditor on that team either kept their mouth shut because how funny the end result would be or was ignored.