Character mistake: While waiting for the plane with Team USA Herb Brooks watches TV news reporting that the NHL All-Star team has been defeated by the Soviets 6-0 in Game 3 of the 1979 Challenge Cup. The 1979 Challenge Cup took place in February, and Herb Brooks became the Team USA Coach only in June.
Character mistake: When Vladislav Tretiak was substituted by Vladimir Myshkin, Ken Dryden commented on this saying that Tretiak had been Tikhonov's bread and butter for a decade. Viktor Tikhonov became the Team USSR and Red Army Head Coach only in 1977, and he had never coached Tretiak on any level before.
Answer: Since they all came from different, sometimes rival, universities, and thus had no commonality, he wanted to give them someone to dislike together, instead of fighting with one another. If they could all bond over what a bastard Brooks was, they'd come together faster as a team and have a chance of winning.