It is very frequent for Satanism to be confused with the Occultists. Satanists are most often what could be described as "hedonists," while the Occultists, among other parts of their religion, worship Lucifer, or the Christian devil figure.
Occultism was founded by Aliester Crowley, which has no connection to the Catholic Church. According to the Church of Satan, he is not a Satanist, but:
His intention was to found a religion that employed the “method of science and the aim of religion.” It is a spiritual doctrine melding aspects of eastern and Western religion, ceremonial magic and it reveres ancient Egyptian deities as primary figures
The Occultists borrowed heavily from Catholic theology, but backwards. Satan or Lucifer is the creator or positive role model. Lucifer means "light" and the egoism and challenge of God by Lucifer is not viewed as negative, but is something to aspire to. Many argue it is a creation of the Catholic Church because of the similarities in theology, but there is no specific evidence to support these assertions, for example, diaries or letters of Crowley, or conversations with people who knew him that believed this to be true. Later Occultists envisioned their religion as enlightened and a replacement for the organized religions of their day. It is not uncommon for religious people of any stripe to stridently believe their religion is the correct one. But this is used as "evidence" that the Catholic Church is plotting an attempt to unite all world religions and violently destroy the true Christians that oppose these Satanists.
The theory of a connection is a part of the broader New World Order and One World Religion theories, that draw a connection between Vatican II reforms and the push to increase outreach of the Catholic Church to end ages of bitter conflict over religious differences with prophecies in the Book of Revelations that speak about a One World Religion occurring in the End Times. In the Book of Revelations many Christians are led astray and the Church becomes corrupted by the False Prophet. So, if we are in the "End Times" it makes sense the Catholic Church is a good candidate for Satan's influence. Other theories sometimes include the Jesuits, Illuminati or Freemasons as the source of the corruption in the Catholic Church.
Occultism was featured in the viral film "Zeitgeist," which is likely why it seems like it is more common. Part I of the film, "The Greatest Story Ever Told," does not tell the viewer that it is an occultist viewpoint, and so was persuasive to many people. It argues that Jesus never existed through a series of historically inaccurate parallels of the story of Jesus and other religious figures, such as Horace and Mirtha. According to Wikipedia, "there remains a strong consensus agreement among historical-critical biblical scholarship that Jesus lived, but they differ about the accuracy of the accounts of his life."