Stoics were accused of being agnostic or atheist because they weren't participating in the religious traditions of the the greeks at the time. But clearly they weren't denying the existence of god in any way. Azeno was teaching, just like socrates, socrates was accused of being an Atheist. The book doesn't really need a defence on its best reading, says Christ.
This interview of Kai Whiting and Leonidas Konstantakos covers their 2021 book titled, Being Better: Stoicism for a World Worth Living In. Their book provides a short (136 pages, excluding notes) yet highly informative introduction to Stoicism as a way of life. Being Better was written for a general audience, and it is the best book I've read for two types of people. First, for those new to Stoicism, Being Better provides an excellent introduction. It includes just enough philosophical theory and history to acquaint the reader with Stoicism. The second audience is the person considering Stoicism but is unsure it's right for them. After reading Being Better, readers will know if Stoicism is a philosophical way of life worth pursuing further.
Finally, I cannot think of a better book for those who want to give a short, easy-to-read, informative, and interesting book to a friend or family member who is curious about Stoicism.
A video version of this interview is available on YouTube