Because of some shit having to do with hating his dad, as I recall.
I'm glad you can tolerate his art back then. But given the other 5 artists who worked on this, it's like I'm eating a delicious roast beef sandwich and then taste a nugget of turd. He suffers badly in that company. I mean, Leach, Davis, Ridgway, Veitch, Totleben--and in the middle, THIS? Ick.
Worse, he came in at a moment of climax and in plot terms, it's a major cockblocking. Imagine how Davis woulda done it. sigh.