The association isn’t grounded in fact
A common view of the Occult is that it is either Satanic or employs symbols that have long been associated with Satanism. In fact, neither is true. People have talked of the “Occult” for hundreds of years without any Satanic implication. In fact, Occultism simply refers to the study of hidden knowledge and is not associated with any particular religious belief.
Most of the associations between the occult and Satanism only came about in the 19th century, in the wake of occultists like Aleister Crowley and Eliphas Levi. These figures were not Satanists either, but some did use more Satanic imagery, or have since been embraced by modern Satanists.
Many believe the five-pointed star, particularly when drawn within a circle, has always been a Satanic symbol. In fact, the pentagram has been used for thousands of years in multiple cultures without any Satanic or evil overtones.
In the 19th century, point down pentagrams sometimes represented spirit being subsumed by matter, as opposed to a point-up pentagram, which represented the superiority of spirit over matter. For this reason, many 20th century Satanists adopted the point down pentagram as their symbol.
Previous to the 19th century, those meanings associated with the orientation of the pentagram didn’t even exist, and the symbol was used to represent everything from the InGolden Ratio to the human microcosm to the wounds of Christ.
Eliphas Levi’s Baphomet
Levi’s illustration of Baphomet was meant to be a highly allegorical image representing multiple magical principles. Unfortunately, people saw the ugly goat body and the bare breasts and presumed it represented Satan, which it didn’t.
The use of the name “Baphomet” in and of itself caused further confusion, with many people thinking that it refers to a demon or at least a pagan god. In fact, it refers to neither. It first showed up in the Middle Ages, probably as a corruption of Mahomet, the Latinized version of Mohammad.
The Knights Templar were later accused of worshiping a being called Baphomet, which has commonly been interpreted as the name of a demon or a pagan deity, although such beings are completely absent from any historical record.
Aleister Crowley was an occultist who later became the prophet of Thelema. He was bitterly opposed to Christianity and obscenely vocal about these views. He talked of sacrificing babies (by which he meant ejaculating without producing a pregnancy) and called himself the Great Beast, a being in the Book of Revelations that many Christians equate with Satan.
He reveled in the resulting negative publicity, and to this day many people think he was a Satanist, which he wasn’t. He also did not represent the majority of occultists.
Many of the 19th-century occults were also Freemasons or members of other orders influenced by Freemasonry. They borrowed some of the Freemason ritual symbolism for their own occult practices. That connection between the two groups has provided negative impressions of both. Some accuse that the Freemasons are occult by nature, while the various Satanic rumors about the Freemasons (largely inspired by the Taxil Hoax) gets transferred to the Masonic occultists.
Occult thinking has existed in Christian Europe for hundreds of years, and much of it is rooted fairly directly in Judeo-Christian mythology, employing the names of angels, recognizing the world is created by a single God, drawing upon the Hebrew language, etc.
In the 19th century, many occultists remained Christian. However, some were interested in Paganism at the very least as allegory, and the debate over the appropriateness and degree of pagan influences was actually one of the causes of the disintegration of the Hermetic Order of the Golden Dawn, a major 19th-century occult organization.
Today, the occult community includes a very wide variety of religious opinions both Judeo-Christian and pagan. These facts have led to the impression of some that all occultism is rooted in pagan religion. At the very least, this makes it contrary to the Christian religion, and some Christians equate those things non-Christian as being Satanic.