The democratic eu are not a nation-country. A nation starts with a constitution written by a constitutive assembly elected with the corresponding powers (something that by the way isnt the case for the current discussed constitutional treaty but that's another story)

When one considers that the democratic eu is going unilateral, one considers eu as a nation-country with constitutional mecanisms to gather representative actions. Hence a president or a congress have no obligation to enter an inner negociation round to take every decision. Some are decided beforehand and are part of the alloted powers of an elected person.
Since the democratic eu are not a nation-country with no constitution, the situation is that most of the decisions, stances they take are the result of an inner round of discussion, negociations... Talking about unilateralism in that context cant make sense because the democratic eu simply lacks the (constitutional) power of being unilateral.
As told, the next step was to consider a un decision a unilateral move since the un have a similar internal functioning as the democratic eu.

On the other hand, for example, when to illustrate the action of democracy on the diversity in cultures, one assesses the monolithic culture of the champion of the democratic free world, the us as inferior to the already really poor diversity of the democratic eu, suddenly the eu loses its nation-feature to be considered as a patchwork of democratic countries.