Homer occupied a position in Greek life that has no exact modern equivalent. Boys learned letters on the poems and memorised long stretches; papyri from Egypt show Homeric texts vastly outnumbering everything else. Rhapsodes performed them at festivals, including the Panathenaia at Athens, where a rule required the poems be recited in order. Cities and aristocratic families traced descent from Homeric heroes and used the poems in territorial arguments. Alexander is said to have carried a copy on campaign.
None of this made the poems doctrine. There was no Homeric orthodoxy, no requirement of assent, and no institution that could have enforced one. Greeks argued about the poems freely and sometimes rewrote them: Stesichorus produced a version in which Helen never went to Troy, and philosophers from Xenophanes onward attacked the poets for attributing theft, adultery and deception to gods.
Plato made the sharpest version of the case. In the Republic he has Socrates propose excluding most of Homer from the education of the guardians, on the grounds that a god cannot be the cause of evil, cannot change shape, and cannot lie, so the passages showing gods quarrelling, grieving or deceiving are simply false and corrupt the young who hear them. He also objects that poetry works by imitation and stirs the emotions it should discipline. The complaint is instructive: it shows the poems were central enough to be worth attacking, and that a Greek could reject their theology entirely without leaving his religion.