Firstly, I want to be clear that I responded specifically to the idea that "MIT license == somehow bad". Releasing code under GPL is not in any way a bad thing, and I'm not arguing against the GPL. People can do whatever they want, and there are a lot of solid reasons to prefer the GPL. My purpose here is to stick up for fellow gamedevs, because it's absurd to believe that we're not interested in contributing to open source just because we prefer the MIT license. I could name several gamedevs off the top of my head who have contributed in a big way to open source software. Interestingly, they all tend to use MIT licenses.

Back then would you say "system programmers are not going to ragequit the industry just because operating systems are closed source". But instead, they wrote open operating systems. Follow their example. Write a free engine. That's the entire point.

The gamedev industry isn't like other industries. You can't spend a decade writing an engine. You therefore need talent in order to write a competitive non-toy engine. This means you must work in the game industry for a period of time to get that talent. You also need to be brought up steeped in the sort of culture that makes you mentally inclined to open source your years of hard work rather than keeping it closed and proprietary. That's why it's a mistake to villify the MIT license -- you're cutting off an entire generation of programmers from open source culture. Specifically, the generation of programmers who want to be game developers. The reason is because they are going to be working in the gamedev industry, and hence the MIT license is going to be their only option to participate in open source culture. Villifying them will drive them away, and future talent will write proprietary closed-source engines as a result rather than free and open source ones.

In summary, villifying the MIT license is directly counterproductive to your philosophical goal of seeing less proprietary software.