People!
OP! Why don't you just send him an email about it? I mean, it's shown after every single episode.
People! I think we're missing the point where he once said he don't want to control a group of units but rather player one so he can stare his enemies into their eyes, that's your reason!
But remember! On the Valkyria Chronicles he did say he got amused playing it, the actual gameplay that is, not the story/options/"Are you sure?" questions/etc!
Conclusion! Yahtzee may aswell enjoy Strategy games, he just have to try one he likes. I mean, he loves Silent Hill 2 etc while I personally feel for horror games (except Resident Evil 2 and 3) what Yahtzee probably feel for Real Time Strategies.
Yes! I know Valkyria is a turn based, and he seems more into that than real time.
Why he doesn't like him? Like I said, and many others above, ask -him- write -him- an e-mail!