Merlyn a vegetarian?

I've been re-reading T.H. White's The Once and Future King. I'd forgotten that White casts Merlyn as a vegetarian, though a conflicted one:

They were riding back from a day on the mountain, where they had been hunting grouse with the peregrines, and Merlyn had gone with them for the sake of the ride. He had become a vegetarian lately -- an opponent of blood-sports on principle -- although he had gone through most of them during his thoughtless youth -- and even now he secretly adored to watch the falcons for themselves. Their masterly circles, as they waited on -- mere specs in the sky -- and the bur-r-r with which they scythed on the grouse, and the way in which the wretched quarry, killed instantaneously, went end-over-tip into the heather -- these were a temptation to which he yielded in the uncomfortable knowledge that it was sin. He consoled himself by saying that the grouse were for the pot. But it was a shallow excuse, for he did not believe in eating meat either.

Later on, Sir Galahad is described by Sir Gawaine as "a vegetarian and teetotaler", though as Gawaine's assessment is that Galahad is a prick this isn't a compliment.