If Huffman had called up guys like Christian Selig a while back and been like "Listen, it's been great, I love the apps you guys make, but business is business and I want to see more revenue, and to do that I'm going to charge more for the API and probably eventually shut it down, let's work on a timetable to sunset things.", he's not nearly the jerk he is today. No one's under the illusion that Reddit or Conde Nast are charities; they have revenue targets to make.
What makes this fucking people over is the negotiating over API price and implementation timetable that was clearly in bad faith and meant to shut down these applications within the timespan of a quarter. Imagine being told that your way of making a living (which these apps are for their developers) is going away in a month. Sure, these devs are the cream of the crop, but that's still a major life disruption, and you don't do that to the people who helped make your website what it is today.
This isn't just about an API becoming paid. It's clear they want to phase out 3rd party apps without saying it out loud.