I don't know that there's any irony there. In my reading, the passage is actually advocating against such laws. And is aimed at the kind of thinking that leads to such laws.
I don't think he is condoning or advocating for such thinking in that passage - more saying that, if you do want these kind of laws (while he lists some contemporary examples) you have to realise that it won't actually work and will have other, negative consequences. That's not him necessarily condoning the thinking or actual moral standing of those examples. Just pointing out what he sees are the realities of such laws.
Oh no! Kerry Greenwood read my self published novel a few years back and said some very nice things and even let me quote her. Rereading her emails had been a great boost in confidence as I struggled with writing more things. And she was very kind (and funny) in the small exchange we had. I had planned on sending her the sequel at the end of this year. This is very sad news. Condolences to you and hers.