Shapiro is what you get when you take an intelligent person and corrupt their mind with religious fundamentalism.
I was originally intrigued by him because he seemed far more intelligent and more intellectually honest than other conservative media personalities. At least, that’s how he comes across in the interviews I watched. His writing (where there is no one there to push back against him) seems less honest.
I haven’t read his book, nor do I intend to, but I will offer a thought or two on your analysis of it.
First of all, I think it’s a little weird that Shapiro is advocating for Judeo-Christian values, given that he’s Jewish, not Christian. So why doesn’t he just say Judeo values? Oh, right! Because his target audience is mostly Christians.
Regarding objective morality.
The first thing I do whenever I get roped into a debate on morality is to make the argument that what theists refer to as ‘objective morality’ sounds an awful lot like legality, and as we all know, there’s a big difference between morality and legality.
The theist’s argument for objective morality is useless until they offer a good counter for the Euthyphro dilemma, and I haven’t heard one.
Is an act good and moral because God commands it, or does God command it because it is the good and moral thing to do?
If it’s the former, then God’s morals are arbitrary and he could sanction anything, even slavery, even infanticide, even genocide (and there examples of all three being sanctioned by God in the Hebrew Bible).
If it’s the latter, then morality exists independently of God, and we should immediately be wary of someone who claims to speak on God’s behalf about what is moral and what isn’t (especially when that person’s God seems to sometimes be cool with slavery, infanticide, and genocide).