The word occult means hidden. Freemasonry dates from a time when tyrants and Hierophants ruled the world. Back then good men were often tortured and murdered if their ideas were different then those in power. Google “Spanish Inquisition” For more info. Also remember that before Adolph Hitler gassed his first human he banned Freemasonry in Germany. In the Wiki article on Suppression of Freemasonry
https://en.wikipedia.org/wiki/Suppression_of_Freemasonry we find some of the groups who suppressed Freemasonry described as Fascist, Nazi, and Papal. It isn’t that hard for me to imagine that if those groups become all powerful again, as they have in the past, I might choose to remain hidden.
Alchemy and chemistry come from the same root word. They are really the same science. In ancient times chemists would claim to be attempting to turn lead into gold, or to be seeking the Elixer of Life. This appeased those in power who expected to be the recipients of gold and long life. In reality they had stumbled onto (or perhaps had been secretly taught) the fact that it is possible to to refine chemicals and elements from the raw elements of the Earth, and that these elements could then be combined to form medicines and other useful concoctions.
My point is that some things are kept secret for the best and most pure of reasons. In my religion we are encouraged not throw precious things to those who will only trample and destroy them. So it is with many occult traditions. They began in times of great fear and superstition when people with education and intellect were not trusted. The first men to offer evidence that the Earth orbited the sun, and that there were other planets, were imprisoned for their heresies. Even those who claimed the Earth was round did not fair well.
A word of caution before I close this post. We live in a time when many people are mesmerized by facts and often will declare that anything that cannot be scientifically proved has no validity. You however have described yourself as a man with a religious background. In my experience religion teaches many things which can not be scientifically proven. This does not mean that they are not true. Fact and Truth are not the same thing.