Yeah, I honestly listen to it downmixed all the time with no issues. But he’s proud of what he created and wants it shown in the best possible light. I’m sure there are minor phase issues on a stereo mixdown that some careful listener with high-end headphones and a critical ear may pick up, and he doesn’t want the blame for that falling on him, and I understand.
Kinda the way I’m always telling everyone to use Project Threepio’s SUP files and everyone just uses the SRT files and I just privately cringe. It’s the difference between as good as the creator intended and good enough for most purposes.