Obviously I don't know all the details of your story, but I'm still a little skeptical. Yes, there are likely doctors out there that do believe they're too good to get water for patients, but I haven't worked with any like that yet. I have rounded with doctors who have delegated simple tasks like getting water to someone else, but it's always been to either save time or avoid giving water to someone who isn't allowed to get it.
You mentioned you had a tube down your throat—that's probably an NG or OG tube, which is often used for feeding solids and liquids. If you had one of those tubes, then there's very likely a reason you couldn't take solids/liquids by mouth. Again, I don't know all the details, but I'd imagine what happened is that your consulting doctor saw you had an NG or OG tube and wasn't sure why. He probably deferred the decision on whether you could have water to your nurse who would know for sure what you were and weren't allowed to have. The nurse probably isn't aware of what the different doctors know and don't know about their patients and interpreted the request to get water as an ego thing. If my interpretation is correct, the doctor is still wrong in not giving you or the nurse an explanation of what's going on, but the issue is more communication related than it is ego related. I don't believe what happened to you is ideal or how medicine should work, but it's how medicine often ends up working with so many different people having tangential and partial responsibilities for patients.
Based on my experiences working in the hospital so far, communication issues are massive and frequent causes of problems and conflicts between health care providers and patients as well as between different health care providers. Again, the workflow in the hospital is complicated, and I don't believe any one person really knows what any other person should be doing. Each provider knows the extent and limitations of their own role, but others' roles are a mystery. All of this leads to miscommunication, misunderstandings, and massive/frequent problems like your experience.