The consensus seems to be that you did not break any rules by announcing the tie, but it was indeed bad form.
Also, he cannot blame his poor performancce on you. Even if someone tries to "ice" you (which i understand was NOT your intention), your performance is still your own responsibility.
Here is my story, this was my first tourney. After almost four full rounds, I was competing for second place in Grandmasters with another competitor on our card and it came down to the last few holes. I knew it was tight, but did not want to see the scorecard and get distracted by it. With three holes remaining, my card-mate requested that the guy with the card announce all our scores. The card guy asked us if this was okay and we all said no, except for the one player. After a brief conference between the one player and the card-keeper, my close competitor announced loudly that he and I were tied for second.
It is my belief that he was trying to "ice" me because I was acually having a good round and made up a lot of ground. I continued to play my game and ended up getting second place by one stroke, after he tried to birdie the last hole and I played it safe for a par.
Calling out my score situation, even after I had stated my preference to remain silent was rude. But my performance is still my own responsibility.