The fact that you only have Hindus/Indians giving it 5 star ratings further reinforces that this is a book for people who already have a distaste/dislike for Islam and just want something that further reinforces that feeling. Additionally, the reviews go along the lines of "most Muslims will hate this book because it speaks the truth" rather than actual critiques further reinforces that.
Now, regarding the book, once again it seems like its another book written by an ex-Muslim who is looking to make money off of his previous religion. It's one of the many books of this type that all read the same. Nothing new is brought up about Islam and the tiresome trope of bringing up ISIS (and saying they're the most steadfast adherents of Islam) is used.
Quite the boring read.