That is not the point. It was not claimed it is satire, it was claimed by Boehermann (about 3 times in the one minute of the poem) that this is an example of what is not allowed in Germany. He even said that this might get zensored. You cannot take this poem out of context and then judge on it.

The fact that it's about a politician is what should make it protected.

Western democracies have a long and celebrated history of mocking politicians through satire.