Uh glaciers are like a tank of water. Put more in (snow) and it gets deeper/longer, drain more out and it gets shallower/shorter. A glacier is not a thermometer nor something more permanent like rock.
Yet I have read numerous articles on how global warming is melting our glaciers. If warming would melt them, it's odd that their growth is not evidence against global warming. That said, I agree with your post, in terms of the science. The point is that science has as little to do with global warming as it has with astrology ... so we make fun of the True Believers whenever the evidence makes them look particularly absurd (and that's pretty often).