That's what she said...
I really don't think that can be an innuendo in Polish ;)
We don't say this sentence in English. Meat is tough or tender.
Darn :| Well, I think this is something that the non-native speakers will likely not know... but I changed the main answer and created multi-part hints for almost the whole sentence.
Why is this meat so tough? <- not accepted?
Maybe because of the word "so"? The sentence you wrote translates to "Dlaczego to mięso jest tak twarde?"
But "tough" is a better choice in English.
Bo to był w zamrażarce :P
"Bo było w zamrażarce" :)
Hard is not an option?
"Why is this meat hard?" is an accepted option, even though it's not really good English.