The point is that UW argued that they deserved the national championship in 1984 because they considered themselves to be a superior program, playing in a superior conference.
BYU pounding Washington in the '85 game throws a lot of shade on that argument.
Again, everybody knows that '84 and '85 are different seasons with different teams, and nobody is claiming that UW was good in '85. But that's not the point here.
I totally agree that the best response to UW fans is exactly what the OP said: UW had a chance to play BYU for all the marbles, and they essentially chickened out, and now they have no one to blame but themselves for that.