I don't yet see anything contradictory in the 'explosive..air pressure' statement'. Sounds may be mis-interpreted, so must be considered separately. But a high volume, high velocity intrusion of seawater midpoint into a mostly horizontal fuselage could be expected to result in some cabin air overpressure. The paper bag analogy remains viable. Do recall also the fuselage frame pic of the skin neatly unzipped from the intact frame. The most likely cause of that is a sudden, very large, very uniform internal pressure. One must come up with an alternate cause for the unzipped skins to be able to disregard a fuselage overpressure.
Surely the impact that occurred with AF447 would be a good model for an intact aircraft hitting the ocean at relative high vertical speed? I do not recall there being anything that might have been described as some kind of cabin over-pressure 'explosion' due to water ingress. It seems very unlikely that the aircraft would hit in a sufficiently flat attitude, that would avoid a structural break up at critical stress points - meaning there would be no intact pressure vessel to "over-pressure".