Sadly, I am forced to agree with some of the other commentators: you messed up, and it cost you. The book that you read (and publicly endorsed) was, and is, a malicious propaganda lie. You have a responsibility as a public figure to check yourself before wading into the culture wars, especially if you are commenting on something you apparently barely understand. Is it unfortunate that you feel the need to walk away from your job because of this? Yes. Yes, it is. People should know better than to conflate musicians and entertainers with savvy political operators. But still, this is the age of social media, and in case you were unaware, the Trump years have not been kind to political discourse.
“Antifa" is a lightning rod. You, sir, got a zap. It was predictable, and frankly whining about cancel culture isn’t an excuse. If you’re going to endorse a book with this kind of radical right-wing premise, you’re going to need to understand why people might think you’re a Trumpcadet. I’m sorry, it’s harsh, but it is what it is. Treat it as a learning experience, kindly do not fall prey to any more Big Lies, and move forward.