His main goal was to get into a bunny costum and eat carrots all day then finally butt f*ck his brother
He is rejecting the idea that German Austria should be made a part of a future united Germany.
Both men promoted nationalism to unify small states into larger nation-states.
In European countries, political parties and ideologies tend to be associated with colors. The most famous example, which you've probably heard, is that Communists (and often Socialists too) are associated with the color red. A few other examples are:
Bismarck was a monarchist and extreme conservative- firmly a "white" (although he wasn't actually in a political party). He fought hard to strengthen the monarchy in Germany, and the suppress the growing socialist movement of the late 1800s. His efforts can be seen as revolutionary, in counter to the socialist revolutionaries of the time.