I have zero sympathy for these guys, nor for anyone else running their business on free tier infrastructure. This is the kind of customer nobody needs.
Post author here. The article is about alternatives for running your hobby projects. I agree that it doesn't make sense to run, or expect to be able to run, your business applications on free tier. We will keep on using Heroku's great services from now on as well.
In the article, it says they use Heroku for work and hobby projects. I imagine, like many developers with projects on the side, they try out new tech or platforms on the side and advocate for it at work. In this case, I imagine they used Heroku for hobby projects because it was free and brought it to work (where they could switch seamlessly to a paid tier when usage demanded it) because they liked the platform. On Heroku's side of the fence, I would consider this to be a marketing strategy known as a "loss leader". It's fine for Heroku to take that away, but it's also fine for people to be driven away when the marketing strategy that lured them in is abolished.
I can want free shit. If you offer it, I can use it. If you stop offering it, I can leave and look for more free shit. I can also help other people who want free shit to find it. I can write about it, and you can downvote it if you don't like it. The end.