Also, the scholarship isn't about which course of study is more difficult. If you think reading works of fiction and writing papers for hippies is the pinnacle of higher education, then fine. But the scholarship is about which course of study will bring value to the Navy, and the ability to dissect ee cummings' works is on the bottom of the totem pole. Especially as budgets get tight, the Navy needs officers who can bring innovation to solve small scale, everyday fleet problems. It's about the x-factor that technical majors can bring to the fleet, especially at the DH+ level.
Example: I had a DH who was able to automate the mission report through some excel programming. Saved a ton of time, and he's spreading it to the rest of the force. In general, the sub force is woefully behind the technology/software curve, and there isn't budget money available to truly fix it.
Another example: An auxiliary piece of equipment is on the fritz on station. The chief is scratching his head -- never seen it before. The book doesn't contain anything of substance on it. But you have someone with an ME degree who's able to go through the drawings, figure out not only what is wrong, but how to fix it and keep the boat from wasting a 2-3 weeks of deployment transiting to and from station get repairs.
Even on a more simple scale, I can't tell you how many times my Eng, a technical major, had to call bs when a chief wrongfully said 'it's supposed to do that.' Would a non-technical major be confident enough in his knowledge to be able to do that? Maybe, maybe not.
Yet another example: A DH who uses statistical analysis to refine his dept. training program to make it more effective, thus reducing the total time keeping the crew awake for 20+ hours running drills and mitigating the risk that comes with fatigue. Could a non-technical major run a sat training program? Yes. But a guy who hasn't taken a basic stats course ever won't be able to tell you with any kind of confidence whether his training program is actually working the best it could be or where he needs to tweak it. The most he can do is follow the book. And that's 'good enough' to pass inspections, but often it could be better. The mentality of build a model, test the model, refine the model, retest the model, etc. is a line of thinking that is taught in STEM, not English literature.
Those are the types of skills that technical majors bring to the fleet just for small-scale problems and it's why the Navy values them more highly. I'm sure more senior guys can give you a more high-level list of problems that tech majors have helped solve. And I say that as someone with a worthless biology degree.