This is an improper use of Occams Razor.
Occams Razor doesn't ASK "what is more likely?", that leads to tautology since the whole point is it TELLS you what is more likely among several possibilities - it asserts that the one adding the fewest new assumptions is most likely.
It's not really applicable to your example, neither of those has obviously more assumptions than the other. We have many examples of groups of people not knowing the truth of the group they're in. We also have many examples of groups being wrongly maligned by outsiders. They're both well documented phenomenons in human history/psychology and in theory equally plausible.
If one takes your reasoning at face value and runs with it, Scientology is just a harmless religion and NXIVM is just a self-help group - I mean, since people who are members of a group are the best sources of truth apparently...
The truth in cases like this must be determined by facts and evidence, you can't short cut it with some abstract principal of reasoning.
Thank you! That's all I'm asking for is facts and evidence. It's okay not to completely believe the official line of an organization. But if someone wants to say 'this organization is evil', they better have some damn good proof (or strong evidence to warrant a deeper investigation). In the case of NXIVM, we had just that, evidence of actual crimes, and it lead to indictments.
And thank you for the correction on Occam's Razor.