Im not a hockey fan, but I have read the Wikipedia Article about the 1980 tournament, and you are both right and wrong. Right in that the game against Russia (Soviet) was not the gold medal game and that it therefore is a bad comparison, but also wrong when claiming the game was the semifinal.
The 1980 tournament had two groups in the group stage, where the best two went on to the medal round. USA and Sweden from one group and Soviet and Finland from the second group. The games played in the group stage counted twice, meaning that USA played against Soviet and Finland in the medal round and carried their draw against Sweden with them.
That meant then going into the first game, Soviet was on 2 points, USA and Sweden on 1 point and Finland on 0 point. After this round USA was sitting on 3 points, Soviet and Sweden on 2 and Finland on 1 point. When the game between USA and Finland started USA would win gold by winning this match, but Finland would not win gold if they won the match as either Sweden or Soviet would likely gain 4 points by winning their game and if it was a drawn Soviet should win the gold because they beat Finland in the group stage. So the USA-Finland game wasnt even a theoretical "final" in the sense that the gold medal would be decided in that match as only 1 out of 3 possible outcomes would secure gold for one of the two teams involved.
I like the modern concept with knockout games more than a Round Robin medal round.