You point stands but most Satanism actually doesn't actually believe in a literal Satan, they identify with him as an allegory.

The largest sects, The Church of Satan (athiest) and the Satanic Temple (non-theist) don't have a belief in Satan as a deity.

There is a subset that actually does though but they are a minority of a minority.

https://en.wikipedia.org/wiki/Theistic_Satanism