This one is rather interesting. The dealer brain farted, just not thinking. To the OP and to second what Paparazzi wrote, you cannot win a hand that is not shown when the other one is shown. The hand shown wins no matter what it is until a better hand is shown.
You said you were waiting for the dealer to give you a sign as to rather or not you should show your hand, keep waiting. To say it is not the dealers job to tell you that you need to show your hand would be understating the common policy at a well ran poker room. It is against policy for the dealer to do anything but take hands discarded face down and place them in the muck. They should not ask are you sure, they should not remind you that you need to turn your cards up to win this pot, they should take your cards place them in the muck and move on with the game. It is bad practice for the dealer to call the hand with emphasize hinting to you that you need to turn your cards up. Turn your cards up lets quit f'in around and get the hand over.
While I would bet that the ruling was that the player showed his hand and thus won, I would also put a money line on the ruling being a simple case of the pot being pushed to the wrong player. Its would be a really simple video review, one player showed, the other player mucked cards face down, opps the dealer brain farted and pushed the pot to the wrong player.
There are basic reasons why the dealer is not supposed to say anything to you about turning over the cards. The really simple basic rules of poker is that you can win a pot by betting a player out, or you can show down the best hand. There are no other ways to win. This is so basic it is assumed when decisions are made, and in the regular course of the game things are predicated on that every player understands this. Any claim that one does not understand this or that they should be treated with exception, always should be treated as mute BS. It is never the dealers job to protect a player from themselves. I would be happy to tell a player or emphasize to a player they need to turn up their hand to win a pot, after I have placed their cards squarely and with no shot at recovery in the middle of the muck. It is a competitive game, and you lose edge for not understanding the basics of the game, it would be simply unfair to other players to help you at this point.
However the ruling was came to, it was a rock solid ruling that you had to give up the pot. Your remedy to get this pot was simple, turn up your hand. Your opponents claim to the pot was perfectly legitimate. You did not say if eight high beat the board or not, even if it did not, you did not show a hand, you have no claim. If it did not you might get lucky in a ruling were they split the pot. However, if only one hand is shown it does not need to be read, it is the only live hand and I would not consider rather or not your opponents hand beat the board or not.
Remember, unless you have the only hand left on the table you will ALWAYS need to show your cards to have any claim to a pot. Turn up your hand. The dealer is not suppose to tell you to turn up your hand, the floor person is obligated to rule against any claim you think you may have to the pot if you do not turn up your hand. This is basic game play, like rolling twelve in monopoly, you first must roll the dice before you can have any claim to buying boardwalk.