It is actually quite typical that people who are sexually abused/raped/molested, especially as children, do not tell anyone. Add that to her being manipulated by her mother into internalizing it as being her fault, and that she would be unlovable to anyone who knew, then it's not surprising that she has never told anyone. Intelligence, resources, or whatever else it is that your implying should somehow make Rachel a special sort of victim, or not a victim at all, I'm not really sure exactly, but somehow held to a different standard than other victims, I'm not quite getting. And as far as the reveal, I'm OK with it. Her behavior throughout the series--acting out sexually, her dysfunctional relationship with Quinn, confusing sex with power with love, etc. actually make this believable. I would have an issue with this being lazy writing if we hadn't watched almost two seasons of a person behaving in a way that makes this entirely plausible.