I agree, the OP is taking this too personal and the comments about the pilots responding in such a way really does not have anything to do with why your onwards flight to BKK decided to leave on-time and you were unfortunately left behind.
Look man, we all go through this and on an international leg I'd say you made out well by being delayed by only 6 hours. DL themselves only have the single DL283 from NRT to BKK, you should be thankful that you were at least rebooked on a flight that left within 12 hours. In some cases you would have been stuck until the following days DL283, I would say that DL responded fairly well by recognizing that there were a dozen connecting passengers that would not make the flight and they did their best to rebook you on the next available flight that was not even on their own airline. I have faced 24, 28, 32, and 43 hour delays on international flights over the last few years...at the end of the day what I care about most is arriving at my destination safely. Some of the delays have been because of MX, others have been because of a late flight arriving and missing the next connection and no more flights being available for that day. It happens. Have I complained about it? Sure, it's natural to be frustrated especially when you don't understand why a simple thing such as holding a flight for x amount of time which you might perceive as a short amount of time, was not done.
But there are other things that you may not be aware of. First off, there's a very good chance...I would say I'm almost certain, the DL knew what time you and your 11 other fellow passengers were arriving, what gate you would be assigned, what gate your connection to BKK was leaving, and whether they had the ability to hold your flight or if it simply was not possible. In some cases in NRT, they will delay a flight if there are larger number of connecting passengers. I myself have taken DL295 from ATL to NRT which arrived on-time, connecting to DL283...but because of 40+ connecting passengers that were arriving from other NRT bound flights they decided to delay the 283 departure by about 45 minutes. Now, it's easy to point out that well they held a flight for that reason which is technically the same as your reason...but the next day there was no DL283 (at this time of the season it was not a daily flight) so obviously they'd have to look at additional hotel accommodations and since it was peak travel season, another available flight on let's say ANA may not have been possible. Therefore DL decided it would be best from an operational and cost perspective to delay the flight to BKK. Does it happen sometimes? Sure. Does it happen always? No, nor should you expect it to...no one should expect that. The airline decides what is best for its operations, their decision...whether you like it or not. After dozens of delays, canceled flights, IRROPs, unforseen situations, etc. I've come to realize that...the airline decides what is best for its operations, and one of the reasons why I am loyal to DL is because they have always taken care of me in an IRROPs situation. You are more than free to complain to them about how they handled the situation, and perhaps you will get a good number of skymiles as a gesture...but 75k miles? 100k miles? Seriously?
Someone can correct me if I'm wrong on this, but if I recall correctly...NRT-BKK is usually a 2 pilot crew, it's about a 7 - 7.5 hour flight (sometimes an hour less depending on the season)...I am sure that there are limitations on the number of hours they can operate an aircraft per segment with that number of crew...it's not like your ULH that has 4 crew members and they can alternate to get some rest...I could be wrong on that, but it would not surprise me if the flight could not be held because of the crew not having enough hours.
Good luck with your complaint to Delta. I hope you receive a resolution, in this case points or some other form of compensation that keeps you satisfied and allows you to move on from this experience.