I, too, dislike it. (line 1)
The speaker uses the pronoun "it" to refer to poetry, marking poetry's first transformation. Although this change in language (from "poetry" to "it") may seem trivial, notice that Moore never calls poetry by name in the body of the poem. She refers to poetry as "it" a number of times and then concludes by calling poetry "a place for the genuine." The changing names for poetry might actually indicate a broader transformation: a changing conception of poetry's definition.
Reading it, however (line 2)
From the first line, we can't know for sure why the speaker dislikes poetry and whether she dislikes specific poems, all poems, or just the idea of poetry in general. Does she dislike her own poems or other writers'? In the poem's second line, the speaker clarifies that she speaks from the perspective of a reader rather than a writer. She then throws in the word "however." We know from this word that her dislike is not so simple; we can guess that the speaker will backtrack on her initial statement and will, instead, offer a different or modified opinion about poetry.
one discovers in it, after all (lines 2-3)
As discussed under "Form and Meter" and in the "Detailed Summary" of lines 2 and 3, this line break is incredibly awkward. One explanation for it is that it's a remnant of the poem's previous syllabic form. When the poem was 29 lines long, this line break kept the syllable count of line 2 consistent with the syllable counts of the other stanzas' second lines. Once Moore took out her eraser and got rid of the other stanzas (and significant parts of this one), the line break stopped making sense. She left the line break in, though, possibly as a souvenir of the original poem.