Perhaps you subscribe to their principles and don't even know.
Depends on where you look, but a basic premise of Lucifarianism is the honour pursuit and respect for carnality, intellectual power, human progress, indulgence, and individuality. Those are the basic basic principles. A fallen angel, embracing the mental and excluding the heart loving light principles.
Rationality without warmth.
Anyone can be if they choose too, and many of us tap in and tap out on occasion. Those of us who are not will feel it. Will feel an uneasy aura, and if on the receiving end may feel rather perplexed.