Because yall don’t understand idioms no more. It mean you can’t have it both ways. It don’t mean you literally can’t have cake. If you eat da cake it’s gone which means you can either eat da cake or not eat da cake.
My parents were in the middle of an argument when my dad proudly said, “I bought you a house and a car,” and my mum casually responded, “That’s standard procedure.” LMAOOO