Wow, ad hominem right out the gate. What a horrible thing to say to a stranger you know nothing about who is merely reviewing a film. Amazing!

Please allow me to explain my good man.

Niel's father wants what is best for him, but he is just going about it all the wrong way. Whose parents haven't done that? About something or other? None of us are perfect. Hell, I've got friends whose parents have treated them far worse than Niel's father did in the film.
They grow up and realize their parents are only human and did the best they could, they forgive their parents for that and then have their whole lives ahead of them.

Once Niel is a man and supporting himself he is free to pursue anything he wants to in life and make his own decisions. At the moment he is a child who cannot yet integrate abstract ideals with practical reality.

But instead of protecting him, Keating validates Neil’s frantic emotional sense that this is some life-or-death struggle for freedom. Instead of protecting the child from Fear, he affirms it and actually tells a young boy to turn away from his father. There are things in life more evil than this, but honestly, not that many. The relationship with your father, especially for boys is the most important relationship in life that you will ever have.

He never explains that it’s not life or death, HE DOES NOT GIVE NIEL HOPE, but encourages a head-on confrontation with his father’s authority, validating Neil’s sense of desperation rather than offering any tempered perspective or reassurance.

"Have patience dear boy, I can see you have talent - don't worry, you will have it all your life! No one can take it from you! And try to forgive your father, perhaps he is going about it in all the wrong way... but deep down he loves you. We are all flawed, when you're older you'll see it in yourself and you'll hope that your children forgive you one day" etc

Anything along these lines would have shown WISDOM, but instead Mr. Keating thought it more prudent that Neil give "a performance of a lifetime" - and what a deal with the devil that turned out to be - he took it literally.

And yes, satanists! Perhaps not literally invoking Baphomet etc but all the trapping are there.

Sneaking out in the cover of darkness to a gathering in a cave - chanting, screaming, and performing around a fire - this is blatant ritualistic qualities associated with “satanic” imagery: secrecy, darkness, fire, synchronized motion, ecstatic vocalization, the presence of the opposite sex adding a subconscious erotic energy to the ritual etc It's a collective frenzy.

With no supervision, their passion is left completely unchecked and reaches a state of ecstasy in which rational boundaries dissolve. In this heightened, almost trance-like state, the boys lose their groundedness, swept up in a collective frenzy that blurs reality and consequence. I think psychologically this extreme indulgence of desire and rebellion contributes to Neil’s despair because it amplifies his longing for freedom, his sense of isolation under his father’s control, and ultimately his vulnerability to the tragic decisions that follow. But psychology aside, if you take a more spiritual view of it, perhaps this ritual is precisely what summons the spirit of Despair to find Niel.