The option to simply walk to the next tee assuming the putt was conceded violates not only the intent but also the written rules of golf. You are advocating that Kuchar is a "dick" by following the rules?The point is simple. After Garcia swiped at the ball in temper Kuch had a choice.
Either walk to the next tee with everyone assuming the putt was conceded and a half was the result. Had he done that, it would have been a fair result and nothing more would have been said. Kuch dodged a bullet because Garcia should have holed the four footer for a win. A six inch putt should always be conceded in that position, and I doubt any tour pro has been asked to hole a six inch putt in match play.
Or he could approach the referee and claim the hole because he had not been heard to state the obvious. By pointing out to the referee ,unasked, that he had not said out loud what everyone knew to be true, he knew he was claiming a win, lighting Garcia's fuse, and getting something he did not deserve.
The point you seem to avoid is that Kuch had the option to do nothing and let it ride. Had the referee approached him (why would he?), then Kuchar would have been entitled to say he had not conceded the putt, and should have been asked if he wanted to claim the hole. At no stage was Kuchar in danger of breaking any rule, only the unwritten etiquette of the game. By doing so, he had gone from being one of the most liked and respected players on the Tour to a dick.