While it certainly reads satirical, in the sense that someone writing a book like this now would come off comically evil, there is nothing to suggest it was a satire. That's just a reddit thing that's been trending, and largely put forward by one historian a long time ago.

There's plenty of reason to think he wrote this book earnestly to boost his own political standing with the Medici family. It was not written for the common man, it was written as a resumé for political leaders to peruse. However, he distanced himself from the book in his later work.