Have you heard? "What you see is what you get"?
It seems like you are saying that if one denies the existence of Satan then there is no
Satan. Is that what you mean?
Well if I deny the wind, which I cannot see, then the storm approaching won't exist
either.
Fact is tho that, even if I deny the wind I can see and feel the affects, of the wind.
If I deny the affects of the wind then the approaching storm will cause harm because
I wasn't prepared for the storm.
The same logic could be applied to many things we cannot see but can be affected by
what we can't see.
Electricity, heat, and radiation come to mind.
I can't see those things but can feel the affects. If I continue to deny the affects of what
I can't see something then great harm to me could be the result of such denial.