Earlier quoted context omitted.
The problem in this case would be they seem to be hiring almost exclusively from a rather obscure religious group. That means they're illegally discriminating against members other religions.
Cults are not “obscure religious groups.” It varies widely by state (and in federal jurisprudence), but most states have a “free association”-style test: if members aren’t free to come and go, it’s a cult and not a religion. Google would not be exposed to any significant liability here. Particularly not when the cult has a well-documented history of sexual abuse.
Islam for example is a religion, that you can not leave.