It's unclear from the article whither you are correct or you are offering a straw-man argument. Obviously the situation you are positing

1. You posit a distorted idea of "tyranny" - you extend it to all morals

2. You assume a second stage of Satan Worship, which might not be present.

From the article it seems far more likely to be an Atheist club that chose a name to cause debate about the cultural capital religion has.

Bear in mind that for centuries the church has been used as a means of control and to support autocrats and persecution. It's far more likely the Satanic club is objecting to that use.

I can’t figure out if you are serious.

To their credit, that quoted statement rejects the claim that they're a religiously motivated club. They outright state that the worship of Satan is not what they do (because they are non-theistic) and encouraging that would probably have you removed. Either way, moral apathy exists with or without religion, so I'd argue it's pointless to blame it on an optional extracurricular club (for teenagers).

So far, the only instigators of conflict here seem to be religiously-involved adults. So long as individual self-expression is respected, I see no reason why Satan Club should be treated different from a religious fellowship or book club.

Ceding your concept of morality to a book someone wrote thousands of years ago is the pinnacle act of moral apathy. That level of apathy is revealed in the way you make your argument: Others' way(s) of life can't possible be moral because they're doing things differently... revealing a lazy mind incapable of compassion and unable to comprehend the values of others.

Seriously, take a look at what you wrote and think about the implications of painting people involved in Not Your Preferred Religion as "naive followers" with "amoral apathy" that are lured into "actual worship"... which sounds a lot like how certain popular religious organizations slip into the philosophies of others who were better off without them, not that I'd name names. It'd be difficult, anyway, as the hypocrisy is usually thick with individuals who engage in these sorts of mental gymnastics.

It's super common when TST gets involved, and it's always amusing to watch.