Hey! I haven't but the wiki says "Lewis goes on to warn readers about the consequences of doing away with ideas of objective value. It defends "man's power over nature" as something worth pursuing but criticizes the use of it to debunk values, the value of science itself being among them. The title of the book then, is taken to mean that moral relativism threatens the idea of humanity itself." so yeah, definitely.

And, as I see it, some ideologies ("cultures" felt a bit too big of a word) are objectively 'better' (as in, they allow the largest amount of people, perhaps even everyone, to live with each other happily, healthily, peacefully and lovingly) than others. I mean, if one take can be better than another, a collection of takes can also be better than another, right? In fact, denying that is nothing but another expression of current Western ideology. I'm telling you, there's such a thing as objective rights and wrongs that people outside of the Western sphere of influence believe in (in degrees though). In their case, the problems lie in an excess in restrictiveness and unfair treatment/punishment due to it. But I think it's a better starting point than to deny it all, throwing away the baby with the bathwater.