There are two systems out there for the romanization of Hangul, of which I'm sure you're aware. They might've picked one you're unfamiliar with seeing and using, or they really may have invented one of their own for the "benefit" of Korean learners. Romanization, in my view, can have a few varying purposes. To native English-speaking ears, Korean-language words can sound quite foreign, so romanization anglicizes them for easier consumption and pronunciation. There's been a trend to move away from romanization in learning at its earliest stages, as the argument goes that it muddies the ability of the learner to pronounce correctly the sounds of any syllabary and/or foreign-scripted language.
I myself am on the fence about the real utility of such a system. "Invented" or "made-up" systems for digesting languages different than ours have always existed, albeit in different forms. (Koreans use to a degree sometimes a form of system that approximates our English alphabet, and that's how we get creative takes on our native words--loanwords, or other borrowings.) The IPA is a system just like that, "made-up" as any other. It claims objectivity, but for the layperson, can be just as clunky and unclear as even the strangest Americanized romanization gambit. If the underlying logic isn't as incisive and clutter-free as possible, the whole thing might crumble. And that means making a system user-friendly for all, which is a grand task not easily undertaken, as you might know from working in IT. Not every person will understand the system designer's intent in building a system, and not every system designer is sensitive to the needs of the users.
That's why I'm guessing (not remembering clearly all of your log posts) your main gripe is the ease of use of the text you chose to buy. It didn't take the human element into account and went straight for the "theoretical jugular", making something unnecessarily hard to understand. In my opinion, romanization is good if you're pairing it with beginning reading. It's been so long I can't remember myself if I used it to learn Hangul. Either way, I still sound non-native. I probably always will. I've been complimented on my pronunciation and prosody, but I know I've much work to do. Another concern of yours might be that you'll never develop the reading skills necessary to function in Korean, whatever goals you may have for yourself.
It's taken me many years to get up to a comfortable reading speed in Korean (with the alphabet not being Latin, or really just different) and I don't understand words so much as I can intuitively zip through them, sometimes without sub-vocalizing, sometimes with (which is to me, personally, a bonus in certain instances). You can read Korean anywhere, and in my experience, reading different types of romanization has only diversified my learning time as opposed to hindering it. I started reading Hangul off videos on YouTube, and once I caught the pattern, I was good to move on to longer passages.
My point here is: not reading full Korean in a textbook won't get you off to a bad start to the Korean marathon, even if you think you're above something that might prove a hurdle. Remember, if you're a track star, you're built for speed, but you must also keep in mind that time is relative and any gains you acquire in the race to the finish line can be stripped from you if you don't train well, or take care of your body (i.e. resting, eating healthily, providing for your mental wellbeing or stamina). It's all psychological, and "whether you think you can, or think you can't--you're right."
A gift:
Korean Romanization Converter