Obviously English is not your first language. And I think that appears to be causing some people to misunderstand what you are trying to say here.
Personally, I am pretty sure I am understanding you.
You are not wrong in saying that it isn't a requirement to believe in magic to be a Satanist.
In his recently published book The Satanic Scriptures our High Priest Peter H. Gilmore points out that it is not a requirement for a Satanist to believe in magic but exploring it may well produce results that convince you of its effectiveness.
Further, I am quite sure that what you are trying to say is that magic is not supernatural or other worldly - rather it is a natural attribute and carnal ability of the human being; if only we investigate it - therefore, it is not a case of believing in it - but simply using it as an effective tool in our lives.
If I am right and that is what you are trying to say then I agree with you.