They told you that "you were very good on the technical requirement". In another word, you were only good on the technical requirement. But they still have other requirements that you didn't meet. That's the true reason you were rejected and it's the typical American way to deliver a message.
You would not be so suprised if you following my advise in my previous post: closing with specific questions. For example, at the begining of the conversation, you should have asked about the key requirements of the job. At the end of the meeting, you should have asked how the interviewer thought you met those requirements, one by one. Then you could find out where you truely did well and where you didn't.