Let me draw an example. The RP is all about telling men the truth about some women, and the way the world works (in their eyes). In my view, they are more right then wrong, but, let me draw an analogy and see if it helps at all.
Imagine if we told young women that men don't care if you're heavy or thin, attractive or ugly, and the way to get a good man is to know how to knit well. Imagine the surprise that young woman would get when she entered the dating market and realized that what she'd learned was wrong, most men (not all, most) were more attracted to thin, attractive women, and didn't care a lick if she could knit or not. She would "take the red pill" when she started wearing sexier clothes, lost weight and gave up knitting (or gave up talking about it on dates).
That's basically the situation we have, young men, or at least speaking personally, me, were taught that women liked men who treated them like royalty; the way to a woman's heart was by showering her with affection and gifts, and a good way to meet women was to be friends with them and see what developed. Well, again, I'm sure this does work for some people, but, in general, it's all wrong. The way to many women's heart is by acting aloof and uninterested, being friends with a woman is a terrible way to generate attraction, and affection and gifts really make you look needy rather than strong. And we actually have a term here for treating your wife like royalty, putting her on a pedestal, and we all say (and I agree) that it's a terrible way to keep a woman interested in you.
The RP is simply realizing that most of the things men learn about women, or, making it about me, the things I learned about women were not true (in general, I'm sure there are some women out there it would be true for, but not the majority). Yes, some people go a lot further (as I did, and I feel bad about it) and realize that it's really easy to "game" and lie to women to have sex building on the RP principals. And yes, there are a lot of sites out there that are dedicated to teaching men the way to game women and the easiest way to get them to have sex. My W's AP was an ardent reader of this stuff because I actually saw lines, quoted verbatim, from books that I read many years ago. Yes, it does work on a lot of women, including my W, had the AP never "studied" this stuff I have no doubt at all he never would have been able to get my W to sleep with him (because, even if she was looking to cheat, he had very little to offer).
So, in a way, I'm happy that your son doesn't believe in the RP, and doesn't take up it's teachings. In another way, I'm afraid for him because in not reading and understand at least some of it, he's not going to be able to understand women as well as he could if he understood it.
Am I happy I learned it? Yes, in some ways I am, it gave me a lot more confidence, it showed me how to attract women and made sex less of a "pressing issue" for me, I knew I could get it, and, for a young man, that's an important thing. But in some ways, I do wish I'd never started down that path. I'm sure I messed up some women in the path, and I'm sure they wondered why I was so impossible to lock down. Some of them I really did like, but I was so "RP'ed" up that I couldn't let my guard down. And then, I did finally let it down with my W, and she cheated on me. Do I think the two are related? Directly, no. But indirectly, yes, I do; I think I let myself slip and our relationship coast without putting the "game" into it that women, including my W, generally find very attractive. No, I don't blame myself, but I also am sure I could have prevented it. And that's a sad realization, RP or not.