This seems a bit unfair
> they have their own weird language, there's a hierarchy, and people on the inside operate under a constant threat of ostracism.
Most groups of people are like this to some extent. Most corporations are like this. Cultiness is a spectrum, and the comparison to scientology is a bit much as scientology does much worse things than that.
> Over and over I keep coming across EA arguments that could be used to justify almost literally any behavior, so long as you can tell yourself a story about having a long-term positive goal.
What you describe is a little too outcome based for my preferences, but you act as if outcome based morality isn't a common view. That viewing your moral standing as what the result of your actions are; how much happiness you have caused minus how much suffering is instrinsically unreasonable.
As far as "telling yourself a story" - that's how all morality works. There is no santa clause making a list of naughty or nice. You have to judge for yourself. Sure there are other metrics. I personally value intention, acting with honour, and ensuring the things you do can be universalized, but at the end of the day i am the one who has to verify of i a living up to my own moral precepts. If i wanted to delude myself into self-justifying something bad, it would probably be pretty easy as there is nobody but myself to stop me. I would even argue that is what being moral is: how resistant you are to petty self-justification.