It's not a long document, but to take one of the example torts mentioned: torturous interference with a business contract is illegal, even if you own the means of interfering.
Could matt/automattic/wordpress.org/wordpress.com (they all act as the same entity: matt) have withdrawn services in a way that didn't tortiously interfere with a business contract? Of course. But he didn't, because tortiously interfering with WPEngine's customer contracts was his primary goal. His complaints about cost were secondary at best, and seem to have been entirely a pretext.
To add more perspective: withdrawing services from everybody usually requires one to simply stop working and/or paying bills. To withdraw services from WPEngine, matt had to consciously expend time/effort/money, just to interfere with WPEngine's customer contracts. Doing nothing would have been less work and cost matt less.
Could matt/automattic/wordpress.org/wordpress.com (they all act as the same entity: matt) have withdrawn services in a way that didn't tortiously interfere with a business contract? Of course. But he didn't, because tortiously interfering with WPEngine's customer contracts was his primary goal. His complaints about cost were secondary at best, and seem to have been entirely a pretext.
To add more perspective: withdrawing services from everybody usually requires one to simply stop working and/or paying bills. To withdraw services from WPEngine, matt had to consciously expend time/effort/money, just to interfere with WPEngine's customer contracts. Doing nothing would have been less work and cost matt less.