Here is my essay for the Libertine I which I can use as a tableau to springboard through the Libertine II and thus into formal membership in the MCoS as I am suitably impressed with the quality of such a young organization. You can view this short essay as the foundational level of my own philosophical and literary form of modern Satanism.
Religions, especially those of a spiritual nature, are based upon ethics, morals, and values that are fundamentally anti-life (thus the frequent emphasis on "rewards" in the afterlife) and anti-human (by promoting actions which are contrary to human nature and against an individual's rational self-interest). Understanding how the religious values of the Judeo-Islamic-Christian religions are inversions of what is good or bad for human beings is a fundamentally important concept to grasp about Satanism. That is why we have the inverted star as our symbol. Anton LaVey created modern Satanism as codified in the Satanic Bible as a statement against those hypocritical and anti-human standards. Human beings who belong to such right hand path spiritual religions are "decent" only to the extent that they ignore or act in defiance of those anti-human ethics.
Furthermore, the institutional structure of churches/religions is political in actual nature and serves to pressure the individual (through guilt, fear, or priesthood "authority") to submission to the will of the religious institutions (often, of course, with a sizable tithe or offering). Satan, as defined by Pike and emphasized by various modern Satanist organizations, represents the archetypal hero with the ability to stand up against this institutional religious oppression through the encouragement of doubt, critical inquiry, freedom of thought and belief, and the refusal to subjugate the rights of the individual to the collective. Modern Satanism itself then is a paradox as it may use the techniques of institutional religions, such as ritual and pageantry (see the Books of Belial and Leviathan in the Satanic Bible), as well as planned "blasphemy" (see the Books of Satan and Lucifer in the Satanic Bible) as a way to undercut the authority and appeal of such institutions which would ultimately include itself.
It is only doubt which will bring mental emancipation.