All- you can learn from Marx, you can learn from Alinsky, you can learn from anyone.
So Coulter is not perfect. That means you read her book from that perspective, and see if anything she says makes sense.
Let’s judge the content of the new book.
Trust who you like. Learn from who you like. If Marx wrote a book promoting capitalism as good, would you believe him? Then why would you trust a person who writes on saving America by a person that promoted a man whose whole career was one big act of opposing what it stood for?