Colonizers vs migrants:
Let me help you understand the difference, Who appointed the chancellor? Who is passing laws and enacting mandates? Who control the police and military?
I see, it's not only your manners that's lacking, even your education is lower class. It feels like you only read the table of contents when studying history.
You're just living in full paranoia, asking other people to erase their identity because they're different. I advise you to travel abroad more and make friends with people from different cultures. Every country in the world, except maybe North Korea, has people from different backgrounds who are proud and attached to their heritage, religion, language, and culture.
There are many german diaspora abroad who are attached to their culture and don't let go of their identity, they even establish their own political parties and organizations, by your logic the germans are colonizing other countries, right? You're delusional
If you want to repeat Brexit, go ahead. The world would be thankful for a new laughing stock.