>> Sure, you can use superstition as a slur for things you don’t believe in.
> I’m not dictating what the word means
That is precisely what you are doing by trying to insinuate that I am using a "slur". You do not have the authority to conjure a belief system out of thin air, assert that it is true without evidence, and start dictating to people the manner in which they are allowed to speak about it.
Why do keep pretending to not understand? I’m not asserting anything regarding the existence of any gods, or the efficacy of prayer or swearing. I’m only trying to explain to you what these words mean. That is not related to my beliefs or yours.
A prayer is a prayer, even if someone is praying to a god that you are sure doesn’t exist. It’s still not “magic spells”, for example.
But if you want to use the word in its scientific meaning, then Christianity, or Islam or whatever religion, is not a superstition.