What is the joke? Is there any? What's wrong with eating penguins? They're no different from any other bird, other than being a lot easier to catch (when on land, not in water).
I know it's probably not the case but I get the feeling that she shot and retrieved the penguin without leaving Gensokyo, maybe even from the Moriya kitchen itself. That would fit her current common sense.
It tastes horrible besides that when it is tried to boil it leaves some black bubbles (previous experience)
Updated
What kind of meat is this?*Fooh*Who knows?So good, so good*Stab*The Story So Far ⇨ The stairs on the steps collapse, and a tub comes dropping onto where you slid down. That's Scarlet Devil Mansion.