One hundred and seventy years ago, the British and the Russians fought the “Crimean War.” The Russians lost, but even then there was no question that the Crimea was Russian territory.
If Zelensky’s speech is fine, will the Southern States of the US be able to reclaim the more recent Confederacy? If they did, would it be OK for Russia to help them? I think not.
I laugh whenever I hear someone talking about Crimea without knowing the history. Just like you said, Crimea will never be given away by Russia. It will never happen.