It's a great hand, but gets devalued due to conditional probability - if anyone raised preflop, people who call are more likely than strict probability to have high, suited cards. So the probability of someone having KhJh on the turn is higher than the probability of someone having KhJh preflop, because the betting selects for good hands.
In this case, note how Thunder expressed his OP: that he eventually lost the hand (not that he had already lost on the flop). I'm guessing that a fourth heart came out on the turn and river (now HUGELY increasing the odds of people having flushes as there are 4 hearts on the board) and that someone held the Kh. Also note that if the board pairs on the river, it's more likely than statistical that someone has a full house - a set has up to 10 outs against a made flush and two pair has 4 outs against a made flush, so these are drawing live even if they're sure someone has a flush already.
I'd be ecstatic with flopping the 2nd nut flush, but I wouldn't be wedded to it.
