It's true, no one said anything about the Cascades exclusively. Looking over i_like_sun's posting history, it seems a safe bet, though.
And it's also true that had Dave Johnston, Art Davidson, and Ray Genet had any alcohol with them on their Denali climb, damn near anything would have frozen, but would it have given their throats frostbite if they had tried to chug it before it turned solid?
In other words, yes, many alcohols can freeze in some climbing conditions. However, many flask-type-beverages will not freeze at pretty cold temperatures - in such a case, can they cause cold injuries if you drink them?
cheers!