This is the live argument, and it is unusual in that both answers are used tactically by the same people. Humanist bodies want religion-equivalent status when it means humanist chaplains in hospitals, prisons and armed forces, humanist celebrants licensed to marry, and equal treatment in school religious-education syllabuses. They do not want it when opponents cite Torcaso v. Watkins to argue that a secular state school is establishing the religion of secular humanism, an argument that has been run in American courts repeatedly. The Humanist Society, which endorses US celebrants and chaplains, has been recognised by the IRS as a religious organisation since 1939. Read the whole record and the honest answer is that humanism is legally a religion and sociologically not one, and that the mismatch is load-bearing.