There are some communities where the vast majority of posts are by on or two users reposting news articles.
Sometimes they'll summarize below, but they will almost never share their opinions on the article, or even just ask what others may think about in regards to this aspect or that aspect. So the entire feed is just URLs.
I would feel more engaged to comment on those posts, or even start a post in the community, when it doesn't feel like a bunch of robots reposting the daily slop.
They always can. I don't see the point of it being mandatory a person who posts an article give their opinion on it. His complaint seems to be he's mad that he seen an article without a comment already on it? Basically all articles end up commented on anyways. Why does it need to be mandatory there is at least 1 more?