I don't think that bots that post news articles are really an issue, as long as users aren't allowed repost the same article multiple times. The articles are going to get posted eventually. Bots can be more efficient at quickly posting breaking news.
My issue is more with bots that post comments pretending to be users; bots that steal content from other users; and bots that repost old content. These are the types of bots that negatively affect the user experience.