Frost was often intentionally elusive in his use of metaphors. In this poem, by using the universal symbols of fire and ice, he leaves the gate wide open for multiple interpretations.
Although fire and ice are antithetical by nature, one can be as destructive as the other. This poem reminds me of Langston Hughes' poem "A Raisin in the Sun," where he points out that apathy and indifference (in Frost's poem, ice) can be as detrimental as rage and violence (as fire) over time.
See the section on "Fire and Ice" in the enotes reference below.