There's several reasons why this may be: 1. Most of the data might be junk, and so it's just not worth it 2. They want paying customers, paying customers don'

There's several reasons why this may be: 1. Most of the data might be junk, and so it's just not worth it 2. They want paying customers, paying customers don't want this, so they don't offer it for paying customers 3. It's really, really hard to annotate data effectively at that scale. The reason why Reddit data is being bought is because it's effectively pre-annotated. Most users don't follow up with chat responses to give feedback. But people absolutely provide answers and upvotes on forums.