I am a self-taught developer and probably had 10 years experience in web development when I first read Code. I would have these little moments of revelation where my mind would get ahead of the narrative of the text because I was working backwards from my higher level understanding to Petzolds lower level descriptions. I think of this book fairly often when reading technical documentation or articles.
I recently listened to Jim Keller relate engineering and design to following recipes in cooking . Most people just execute stacks of recipes in their day-to-day life and they can be very good at that and the results of what they make can be very good. But to be an expert at cooking you need to achieve a deeper understanding of what is food and how food works (say, on a physics or thermodynamic level). I am very much a programming recipe executor but reading Code I got to touch some elements of expertise, which was rewarding.
Imagine a carpenter spending their time getting a chemistry degree in order to better understand how wood glue works.
If your goal is to be a carpenter who puts together housing frames, you absolutely don't need depth. You're also interchangeable and get paid union blue collar wages. On the other hand, if you want to be a craftsman who invents new wooden things, you need depth in some direction, be that structural engineering, artistic, or otherwise.
There's a ceiling you hit unless you learn much more of this stuff. The direction is your choice (but new APIs ain't it -- we're talking depth).
What I actually want to say is that OP shouldn't feel guilty about not knowing those things. It's okay to want to master these things, if it's what you want. But it's pointless to feel bad about not knowing them.
The true philosopher, motivated by love for the truth rather than pride, is so noble in spirit that when she sees evidence that she may be in error, she immediately investigates it rather than turning away; and if she discovers that the evidence is valid, she immediately changes her position. I see such nobility so routinely among mathematicians and logicians that it is noteworthy in the rare cases where it is absent. I see it rarely outside of that field; in some fields, like psychology and theology, I do not see it at all. So I conclude — tentatively — that excellence in mathematics and logic promotes humility and nobility of spirit, which is the highest and most praiseworthy kind of excellence.
So, while I do not think the OP should feel guilty about not knowing those things, I also do not agree with the implication that there is nothing praiseworthy about knowing them.
At the same time, I maintain that we shouldn't feel guilty if we aren't doing it that, for whatever reason. Sure, sometimes we actually want to pursuit some of these things, but don't. Maybe it's because we have a messy schedule, we can't organize ourselves to prioritize passions.
Feeling guilty does little to actually make you pursue your passions. You're better off learning about habits and how to pick ones that serve you.
I heard an expression this weekend that I think is apt - a computer is to computer science as a telescope is to astronomy.
"Computer science is no more about computers than astronomy is about telescopes."
(Also, "CS could be called the post-Turing decline in the study of formal systems." But I don't know for sure if that was Dijkstra. It's one of my favorite jokes.)
I did start getting lost around the second half of the book.