As TFA says, the problem is the anti-tivoization clause, which creates issues for web developers, issues which weren't there with the previous licenses and that should push more people to buy commercial licenses as insurance.
No, the article does not mention the anti-tivoization clause. The AGPL requires you to share the source code with users, even when the software is hosted on your machines. That's what differentiates AGPL from GPLv3.