As I understand it 'Germany' is a collection of 300 city states unified under Otto Von Bismark. 300 City states that for the most part were never subjugated. Not by the Huns. Not by the Romans. Austrians are Germans the same way Belgians are Germans the same way the Nordic tribes are Germans. Genetic testing shows the dutch are German as well. In fact most of Europe is German. Calling people 'German' was a little like a precursor to calling someone white. It's a term that encompasses a lot of smaller ethnic groups that have co mingled significantly and of course it's a political and geographic term.

British people are German too. At least half or so are almost totally German. The Angles and Saxons invaded the east of the Island and would go on to dominate politics there. To this day there's more 'Anglos' in the east then there are Celts. The Celts, Scots, Iberians, and most all european people share Germanic blood. Some are more Germanic then others though.

Some people share German blood but are not German. One of those groups: The Ashkenazim Jews. They bred into German lines with the sole intent of subverting and destroying Germanic peoples, their custom and culture. You can't be of a group that you seek to destroy even if your blood might share some markers of that group.

Hitler Mentions Austria in his April 28, 1939 speech to the Reichstag

One. Austria, the oldest eastern march [Ostmark] of the German people, was once the buttress of the German Nation on the south-east of the Reich. The Germans of that country are descended from settlers from all the German tribes, even though the Bavarian tribe contributed the major portion. Later this Ostmark became the foundation of a centuries-old imperial realm, with Vienna as the capital of the German Reich of that period.

That German Reich was finally broken up in the course of a gradual dissolution by Napoleon, the Corsican, but continued to exist as a German federation, and not so long ago fought and suffered in the greatest war of all time as a political entity that was the expression of the national feelings of the people, even if it was no longer one united state. I myself am a child of that Ostmark.

Not only was the German Reich beaten down and Austria broken up into its component parts by the criminals of Versailles, but Germans were also forbidden to acknowledge that community to which they had declared their adherence for more than a thousand years. I have always regarded the elimination of this state of affairs as the greatest and most sacred task of my life. I have never failed to proclaim this determination, and I have always been resolved to realize these ideas that haunted me day and night.

(Anybody that's more studied up on this though is welcome to correct me; I'm always open to good faith input and quality sources)