Technology

I'm not the guy you responded to, nor am I a kernel expert, but I have a few suggestions:

1. Sites like phoronix and lwn will go into pretty low-level kernel details like this from time to time. You could consider subscribing to their RSS feeds or something like that

2. Review a few open university courses on either Operating Systems or Computer Architecture. Short of that, you can also just browse wikipedia for articles on these kinds of topics. I find it enjoyable to read them from time to time

3. Subscribe to the LKML (which is probably a lot more information than any single person can process, but sites like lwn and phoronix highlight/summarize from time to time)

I would also say that there are a lot of people out there who have made contributions to the Linux kernel, including this specific portion of the Linux kernel. The person you're responding to may even do it as a part of his/her day job (and it certainly reads like he does). It's not that uncommon.

And the last thing to keep in mind is that learning knowledge like this doesn't happen overnight. You learn a lot more by learning small things over several years, compared to learning a lot in a short time. Don't make it a goal to learn things like this - instead, try to make it something you enjoy doing, so you keep doing it over the years and learning more and more small bits of knowledge over time. Eventually, all the different pieces start fitting together and you too could mash out an excellent post like GP's!

This one is really good. It's not super new but that doesn't matter too much because the ideas and concepts underlying modern operating systems don't change very fast. https://www.oreilly.com/library/view/understanding-the-linux/0596005652/

You might also look into programming with a low level language, such as C, C++ or Rust.