White was winning twice as many points as black (64 points for white, 36 for black; draws give 0.5 points to both players) and points difference is all that mat

White was winning twice as many points as black (64 points for white, 36 for black; draws give 0.5 points to both players) and points difference is all that matters for Elo. As a matter of fact, 64-36 is pretty much exactly what you'd expect when two players have 100 Elo difference. Your incorrect perception comes from the fact that, at very high levels (as shown by this match as well), draws become way more common than for lower levels. A 3400 vs 3300 Elo match might be 28-72-0, a 1400 vs 1300 match might be 60-8-32. At the lower level, you see one player winning twice as many games as the other, at the higher level you see one player losing all the time; that looks different to you, but as far as Elo difference is concerned the two results are exactly the same.