It is immature to fight on the internet.
Henry has just read an angry reply to a political opinion post he made.
Henry wants to back his opinion up with more information.
Henry responds with a link to a website with facts that back up his post.
Henry responds to the commenter and gets into a heated argument with him.
The other people reading the thread are exposed to new information.
The other readers focus more on the argument than the point that was made.