The fact just is that some people, like me, really really dislike the concept of "furries".
So I dislike pandas and even worgen with a passion. For whatever reason Tauren don't give me negative vibes as badly as pandas and worgen do.
I absolutely don't mind Draenei and love how the female models look ingame. Sexy stuff. But pandas make me think: "fuck this sh*t!" and are way over the top on the "furry"-scale and the only reason why I really didn't want them to become part of the warcraft universe. I'd rather have them remained mysterious and as NPCs.
The damn female pandas look like the Rescue Rangers... and creep me the fuck out. (Luckily with some simple game setting tweaks you can make the pandaren and worgen races look like another race).