Within a poem several competing forces can be in action - sound vs sense; form vs content; readability vs density etc.
When readers are aware of the options they can more readily appreciate the choices that the poet makes - e.g. how a rhyme scheme might be relaxed to allow the use of a more apt word.
But sometimes readers might only see the losses and miss the gains. Some forms (double acostics for example, or parodies) can be rather obscure yet are quite constraining. In such situations I think it's reasonable for the poet to ensure that the reader is aware of the constraint - knowing the competing factors lets the reader appreciate the craft of the poem more.
A poem's exposed to external influence too, issues not strictly related to poetry. The poet might be working under censorship, or the poet may not wish to write about certain things in case their family and friends read the poem. The poet may write to suit the tastes of a certain editor, or be asked to change some lines by an editor. Poets might not even be aware of the limitations they're working under - they may be "victims" of their upbringing, reading, culture etc.
In such conditions how should the reader react? Just as an awareness of a poem's form might explain why a certain word's been chosen, so awareness of the writer's sociological context could explain a word choice. The reader may even know more about the poet's restrictions than the poet realises
How much disclosure is helpful in these situations? The constraints the writer worked under (be they sociological, or formal) help explain what would be otherwise sub-optimal word choices. The author's bio in a magazine or book can be of legitimate value.