Germans regret it now, don’t they?
They chose what their society thought was right, so according to their society it was right. Plus they were manipulated.
Back to democracy. According to democracy it wasn’t right. Democracy says that all conflicts should be resolved diplomatically, never by force and oppression. So it was wrong even according to our society today. You’re free to have your own opinion about it, but as I mentioned, you’re not in the position to make your opinion a law.