I don't know about the author's approach to this matter, but if I would find out that a company is making a killing using my software and then that company would refuse to even give me an interview I'd probably stop loving doing what I do. Sure, the software is under MIT license and it was the author's choice to do so, but what's the point of doing it under such a license when you can't even count of it mattering in a resume? What's the point of providing free labor to a company with revenue in billions? If you look at the author's blogpost, the only benefit the author mentions is making the number of downloads go up and that's just pathetic.

I am reminded of an another, similar case with a library called "FluentAssertions". This library used to be free to use by anyone until the author changed the license and started charging money for commercial use. The author did that because he spend several year maintaining the library on his own time and dime and megacorpos like Microsoft wouldn't even bother to donate despite using it extensively. What happened afterwards was that the author got shat on by everyone on the internet for daring to ask for money. In the company I work for his library has been replaced with an another free fork at a incredibly fast pace. All that free labor and the author got dropped as soon as they fell out of line.

The worst thing is that it wouldn't probably take much to make the author of the library happy. Even if they weren't interested in hiring him they could still acknowledge him, talk to him a bit to maintain good relations, throw him a nice donation as a thank you and now it would be a nice, good PR story instead of an another reminder that corporations are just looking to squeeze out value out of all of us.