Bad phrasing. The argument is more like "If [this awesome thing X] wasn't available, people would have to find a maybe-less-than-desirable alternative." The name for it is practicality.
Earlier versions of ME (the one with an ARC core) used ThreadX RTOS --- proprietary, commercially licensed. I guess Intel eliminated a huge chunk of those licensing costs by moving to x86+Minix instead.
They chose Minix, so it seems reasonable to assume that Minix was the best option. If Minix would not have been BSD, they would have had to choose a worse option or spend significant money to build their own OS. Both options would have cut into ME's budget and might have reduced its capabilities.
"If A wouldn't, then B would" is a weird argument imho. It's basically equivalent to saying "If we can't destroy C in one blow, there's no point in attacking them".
And security and many other things. Surely you aren't arguing that an even more closed environment is ideal just because of a minor budget spend for a large company.
