The missing context is that he was quote-tweeting a thread by Sandy Petersen titled "How Quake …

The rest of the context leading up to "Sorry, Sandy" has me a little confused, can anybody who knows more explain this bit? > One real problem that I don’t accept the blame for is that we were insisting that level designers be not just game designers, but also have strong visual design esthetics. They needed to make things that not only played well, but looked awesome, and it got more challenging as the technology provided a richer palette. Romero covered that well, which set our company expectations early on. > We should have figured out how to pair up artists and designers earlier, but there was infighting among the designers, and the ones that could manage the visuals were happy to disparage the ones that couldn’t. > Sorry, Sandy. Is he saying that it was a mistake (but not his mistake... Romero's perhaps?) to demand that game designers were also artists? And that this resulted in …