While I agree with the conclusions of the other posters, I also think it is difficult for anyone to put themselves into the shoes of these people, traveling over, waiting for the opportunity. Pitches can go bad quickly. I think anyone knows the pitch that you enter well-prepared and in best spirits and you come out 10 minutes later and wonder what the hell just happened.

Anyway, I also think it's great that you posted this in this detail, since it also shows once more that the interview will give you VC type questions and not YC type (well-informed) questions. If you can't explain it to a VC who is not up to date with everyday tech changes, then you're not ready for YC.

Finally, you sum up the feelings nicely - that mix of a feeling for redemption and the highly illogical feeling of a need for 'revenge'. I have felt that and it is so much unlike my personality, that I was really startled by it. Put that negative energy into something positive, right now I think your first priority is to make a non-tech person understand what it is you're building.