OK, so this is not a well thought-out hypothesis and if you prodded a little I’d probably admit that I do not believe in this, but still: newspapers adore trolls.
Here’s what I observed. In the early days of letting people comment online underneath newspaper articles (was this when the papers feared they had to compete with blogs?), a lot of the time you could respond pseudonymously. Then after some time the papers would force you to register and log in. They said this was to stem the tide of trolls. Except this can hardly be true; trolls play a bigger part in online newspaper comment sections than ever before.
Maybe, you’ll say, this is just human nature. Maybe everybody acts like a pig when they can hide behind a mask. The thing is, I know enough blogs that run a tight ship in their comments sections, making sure discussions stay on topic and insult-free. Unlike the aforementioned newspapers these blogs are run by amateurs with much less disposable time.
Your second argument could be that just because newspapers haven’t figured out how to stop trolls, doesn’t mean they like them. So I need a second hypothesis to answer this: newspapers benefit from trolls (and that is why they like them). If you have trolls, it means you are going to get angry retorts. Trolls are very effective in letting people stay longer at a newspaper’s website which in turn means that people are exposed for a longer time to newspapers’ advertisements.