You are right. It would me much easier for us to require academic degrees. There are still ways to get a work permit for non-EU engineers without a degree, but its much more difficult and subject to a lot of arbitrariness. In some cases, it required months-long battles and countless appeals with the german federal agencies and thats already with support from the city of berlin. It's a difficult situation for all parties involved and we always warn candidates who might not qualify for an "easy" visa about the implications.

Unfortunately, the world is not and has never been a fair and equal place. Most people from western countries do not realize of privileged they are.