I have come across this interesting thread while reading on Pantheism, which lead me to create an account on this forum so I could also give my share on the matter.
I do not think there is a single etymological truth in relation to the concept of Pantheism. Especially with so many variables of the term. A naturalistic pantheist, it seems, uses the word 'God' mainly as a metaphor to describe the mystery and grandiosity of the Universe - the origin of and home to all things. A naturalistic pantheist abstains completely from all that is supernatural and not only concepts related to an anthropomorphic God. The Universe or Nature itself, as well as the feelings of reverence and awe caused by it, have nothing supernatural. An atheist can consider himself a pantheist as far as I'm concerned.
The reason why so many atheists consider themselves pantheists (naturalistic) is because they feel the need to allocate an additional, concise definition, and demonstrate their spiritual and philosophical beliefs beyond the mere denial of God or gods.
As mentioned here already, the
theos in Pantheism is not the actual
theos. That is why Richard Dawkins described Pantheism as "Sexed-up Atheism":
Pantheists don't believe in a supernatural God at all, but use the word God as a non-supernatural synonym for Nature, or for the Universe, or for the lawfulness that governs its workings. [...] Deists differ from pantheists in that the deist God is some kind of cosmic intelligence, rather than the pantheist's metaphoric or poetic synonym for the laws of the universe. Pantheism is sexed-up atheism.