This entire subthread seems to be an argument over the definition of "intelligent". In no dictionary definition that I can find does it exclude people who join cults. Yet that seems to be the argument being made here.
From the Wikipedia:
> No True Scotsman, or appeal to purity, is an informal fallacy in which one attempts to protect their generalized statement from a falsifying counterexample by excluding the counterexample improperly.
So I think it's a No True Scotsman argument to make to say "well, if they joined a cult, they must not have been intelligent in the first place."
But now I suppose we're arguing over the definition of the No True Scotsman fallacy and that's just a bit too meta for me on a rainy Sunday afternoon, so I'm going to go walk my dog. :-)