How can you be banned from the fediverse?
That said, if you insisted that some "Germany's Independence Day" existed, then it's perhaps that what got you banned. Germany was never really a colony. Not of UK, not of Spain or Portugal, or not in newer times of Russia. Many countries that were a colony of them, or just annexxed, have an independence day. Germany doesn't --- the last time it was partially colonized, in roman times, there was no Germany.
Perhaps you mean the reunification day :-)