This really doesn't add up to me. I don't have the numbers, but I would assume that:

1. A very small percentage of website visitors will end up paying for a subscription.

2. They make way less than $5 per user per month from ads.

The money they'd lose by providing an ad-free experience to paying customers should be a rounding error. Removing ads will also increase conversion, but who knows whether or not that will be enough to offset the revenue lost.

I don't particularly care about their "business reality" - if you're an online news outlet you're not paying the costs of printing and distribution - your expenses are just journalist salaries and the marginal costs of keeping a website running. If you need to charge anything close to $5 per user per day to keep such an operation running, you should be out of business.