Quick English lesson for everyone. The word “God” is only capitalized when it is being used as a proper noun, not when it is used as a common noun. Capitalizing “God” but not “gods” is not a monotheist slight against polytheism that implies that Yahweh should be given some sort of orthographic reverence that all of the other gods don’t get. It’s purely because monotheists use the word “God” as Yahweh’s proper name.
This is exactly the same as the capitalization of the words “mom” and “dad.” When I write to you, “my dad bought me a unicorn,” I do not capitalize it. When I write to my brother, “Dad bought me a unicorn,” I capitalize it. I capitalize it when I am using it as a proper name. Ditto with “God” and “Goddess.” When you’re talking about someone named “Goddess,” you capitalize it. When you’re talking about someone else who just so happens to be a goddess, you don’t.
This is not oppression or lack of respect to the gods of polytheist religions. This is just how the English language works when you write it.
So, the following sentences are written correctly:
“I pray to God.”
“I pray to the gods.”
“Hera is a goddess.”
“Yahweh is a god.”
“Wiccans revere the Goddess.”
“Jim Morrison is God.”
And yes, that means the following sentence is also written correctly:
“My favorite god is God.”
The same goes for other words used as proper names for assored deities. This is why we capitalize “the Lord” when referring to Yahweh but not “a lord” when referring to an aristocrat in general. But when you directly address that aristocrat by his title–and manners dictate that you should–you call him “Lord,” capitalized. You might capitalize “Lord” when it is part of a title, such as in a deity’s honorific, but not when used descriptively. So therefore while you might say “Zeus is Lord of the Heavens,” and capitalize it, you would also say “Zeus is the lord of many awesome things, including lightning, fatherhood, Mount Olympus, and meting out justice,” and not capitalize it.
Of course, the exceptions to this rule of capitalization are the same as with any other word. Continue to capitalize the common noun, “god” when you use it in the title of a work, such as Kerenyi’s The Gods of the Greeks or Gaiman’s American Gods (by the same token, do not capitalize it when you use those same phrases in sentences, such as, “the gods of the Greeks were sexually active,” and “money and celebrities are truly American gods”). Also, capitalize it when it’s the first word in a sentence, like always.
Overcapitalization is a sin punishable by ridicule and mockery.