Pallas depiction of her victory over Neptune/Poisedon for the patrogane of Athens is the idea of the benevolence and austerity of the gods, their ways are not our way and fromthe god's point of view, they do not owe mortals any explanation, there is also the image of the blasphemous mortals whose arrogance can exceed no limit.
On the other hand, Arachne depicts how flawed the gods can be by showing in her work eighteen moments that the gods took human form to seek sexual pleasure.
In the end we can see that the myth is about power, the ones in power like to see themselves as benevolents and may justify their actions on the grounds of how difficult it can be for someone who does not know politics understand their ways, on the flip side, the population points their fingers to the abuses and miscarriages of justice the ones in power can commit.
