Some comments from James Zetzel, discussing whether Catullus 34 was written as a hymn for performance at an actual religious festival (he thinks it wasn't):
....Even if Catullus 34 were found in an ancient equivalent of "Hymns Ancient and Modern" that would not mean that its religious aspect was primary in its author's intention.
I realize that I am here committing the intentional fallacy, and I am doing so intentionally, because I do not believe that it is a serious critical problem. In any case, given the assumption--and it is an assumption--of poetic intelligence and control of the text, and given the assumption that we are ultimately interested in the poetry and its composition rather than in using it as evidence for something else, a critic must deal not only with what the historical circumstances are, but how the poet uses them; not with the reconstruction of the psychology and emotions of the poet, but with the depiction of them in the poem; not with what the generic conventions are, but how the poet manipulates them.
From 'Roman Romanticism and Other Fables', p. 50, in The Interpretation of Roman Poetry: Empiricism or Hermeneutics? (entire article pp. 41-57)