Understandable, even if it's sad there won't be an official builder, but the reasoning, in my opinion, is subjective.
Personally to me, after 800+ hours, I never felt that it ruined the perception of the game. Although I might be in the minority, after all, in those 800+ hours I've yet to use a psi build, prefer Trap Expert over Quick Tinkerer, and I love Cut-Throat for it's niche use. In Char Builder I've made 12 builds out of which only 2 are psi users (one TC and one MT). None of these 12 builds are super optimized aside from crafting skills, hacking, lockpicking, persuasion and mercantile, basically exploration skills to open up as much content as possible. For these reasons, character builder is very useful to me, min/maxing exploration skills without wasting any points. As for Feats, the progression map is also useful, as it takes your mind off the core feats you need for your build at certain level ups and allows you to chose what I call auxiliary feats, such as the aforementioned Trap Expert or Sprint. Even though Underrail has minor roleplay elements (i.e. be a good guy/bad guy), it shines in it's huge combat build diversity, allowing to recreate different characters from a variety of media and/or based solely on items existing in the game, hence why I prefer to call them thematic builds.
Case in point, long ago I, using Character Builder, managed to finish my first and only DOM run on a female Sam Fisher build (Psi-less, Gun-Fu, Unique Pistols Only, Cut-Throat and Ambush). It was right after the Unique buff update, the build was sub optimal and even though I struggled with a lot of reloads, I did manage to beat the game. But I still used Character Builder throughout the whole playthrough, truth be told, I made several per level up builds with exact skill point distribution at specific levels. This is probably where the crux of the problem comes from. Because DOM is so unforgiving (hell, it's in the description), but also has juicy extra content, it forces players to make optimized builds (can't blame them, it says you aren't guaranteed to win), otherwise you need a super detailed build map for sub optimal builds, else you risk having a bad time. And not the "oops I made a mistake here, lets restart and fix that", more like "I ran into a wall headfirst and it fought back".
Even though I managed through excessive trial and error kill big T, by using Hawk+W2C+Ambush+Hoddurform+Flares and finding a specific spot, and getting lucky with the tentacles, I still had this nagging feeling I was way too weak. So while finding the solution during the fight was fun, it wasn't strong enough, and abusing the most powerful TM skill of F5+F9 is interesting to a certain point, hence after that I decided to remake it. It was before I figured out how Export/Import Character works.
Now I speedrun builds on Easy before Exporting them for DOM runs. Still to this day I use Char Builder and my female Sam Fisher build is way more polished from previous experience and knowledge. But lo and behold, it's not super optimized, and it shouldn't be, because in the end it's thematically fun, because in the end Character Builder is just a quality of life tool.