As an object, "Germans" is usually some subset in the set of all Germans. "I met Germans in the park today." --> I met some people in the park, which are German. As a subject, this subset can be the entire set. "Germans are racist." --> Germans are generally racist.

"The Germans" is the subset of all Germans in some other set. "I met the Germans in the park today" --> If you are talking to a colleague, this likely means something like "I met all the Germans of our team in the park today."

As you point out, "the Germans" needs a context, i.e. which set are the Germans a subset of? Without context, that set is the set of all humans.

The question is then, which context does OP provide? And I think this is where our difference in how we understand comes from. I read the title first, so I read it as "Germans (as a subset of all humans) are racist". But, given the posted image, you may also read it as "German officials (as a subset of all officials) are racist", which is probably how you read it. I still wouldn't agree with that message, but I wouldn't reject it quite as strongly as the first one.

I think both readings of the title are valid, and this ambiguity could be avoided by using "Germany" or "German officials"

Another point: I agree that Germany has an issue with racism. But how is an ethnostate constitutionally supported? The constitution straight up bans racism in article 3: "No one may be disadvantaged or favored because of their gender, ancestry, race, language, homeland and origin, faith, religious or political opinions."