No, but people do upload data with an expectation that the data not being used without their permission (unless they do a BSD/MIT/Public domain like license). Otherwise, the platform AND/OR the user do expect the data NOT to be used for purposes other then what it was intended for. Your comment is still your comment, and the hacker news platform also has a say in this. If there had been an opt-in, then fine no problem, but there was none, they just trained on everything available, including downloading pirated books from the internet.
I think it's unreasonable to post anything on a public forum and then expect to be able to control who reads it and for what purpose.
Answering here as it wont let me reply: Just because you feel that something that is public, does not mean you can do whatever you want with it. You can't just copy an article from a news site and paste it on yours, that theft. If you dont agree, fine, but that is the law, and ALL the mega corps have been fighting to keep it this way for the last 20 years. If they want to steal everyones info, fine, then lobby to change the copyright laws and no problem.
Copying isn’t theft, we settled this in the 90s.