Roger Ramjets
Philosopher
A hostile environment qualifies as rape culture in my book.You may be right. But victims shouldn't be expected to automatically open up in hostile environments.
The OP identifies a part of underground porn as rape culture. But that is limited to the fringes of society. Producers are hunted down and jailed, and knowing consumers also face prosecution. They are not tolerated any more than other criminals.
The acceptance of rape in mainstream society is far more troubling. In the US we have a former (and possibly future) president, and a supreme court judge who are both known rapists, but 50% of the country doesn't care because they are their guys. Attempts to prosecute them or even just acknowledge their unsuitability for office have resulted in extreme backlash on the victims. That's a society with a rape culture.
Rape culture
Rape culture is a setting, as described by some sociological theories, in which rape is pervasive and normalized due to that setting's attitudes about gender and sexuality. Behaviors commonly associated with rape culture include victim blaming, slut-shaming, sexual objectification, trivializing rape, denial of widespread rape, refusing to acknowledge the harm caused by sexual violence, or some combination of these.
In such an environment expecting victims to 'open up' about their experience is just another way to intimidate them. The treatment they receive helps to silence other rape victims, to the benefit of all the other rapists out there (of which there are a lot!).