There are several occult and magical traditions that require extensive initiations before sharing their inner secrets. There are others that openly release their rites and offer them freely to any interested.
I myself have greatly benefited from rituals and instructions that were once secret but were released to a larger audience. I have made use of information and rituals easily accessible via books and the internet, and implemented changes to those based upon suggestions and feedback from other sources. And I have contributed my own rituals and exercises to that body of open work (and am in fact working on a “rituals” section for this site).
But I’ve got some stuff I ain’t sharing, either.
In the olden days (Teh Burning Tiemz!!!!!!) pagans and magicians did not share their knowledge because doing so could put them in danger of persecution. Initiation was not just a means of training new members, but of vetting them. (And modern covens still do this, although the vetting is usually a measure of compatibility with the group.)
Other groups did not wish to reveal certain rites or rituals because they were potentially dangerous. Performing a Goetic evocation without having reached the appropriate level of training can cause some issues. A spell which can result in damage or death to another is probably not going to be shared with someone you’re not sure about, especially if you believe that you bear the responsibility for the actions of those you teach.
And sometimes … well, sometimes you just want to have a trick or two up your sleeve. Just in case.
There are plenty of rituals that are available openly, and with the appropriate warnings and cautions. Use them at your own risk. But don’t make the assumption that because you can find them, that you are capable or performing them properly (or even worse, altering them), or that you even have a right to them. We have an idea in our society that we have a right to know everything, and the bottom line is that we don’t. This is especially true in matter involving cultural appropriation, where outsiders feel entitled to consume the ritual knowledge of a particular group on the assumption that “knowledge should be free.”
Knowledge is power. And with great power comes great responsibility. So if you seek my magical knowledge (at least that which I have not made openly available) then you must prove to me that you are responsible enough to have it. You must earn it.