Like a ton of other poets, Cummings never gave his poems titles, so editors just use the first line as the title of each poem. But "my father moved through dooms of love" totally works as a title, since the poem is an elegy for the speaker's dad. The first line-title announces the subject of the poem (the father), the focus on that subject (how he "moved" through life), and the celebratory nature of the poem to come ("through dooms of love"). If we had to pick one line to stand as the title for this poem, we don't think we could have done much better than numero uno here.