Grindelwald never rapes anyone. It's much too easy. He likes it when people submit to him. Usually, it's easy. He lavished attention on them, whispers about how he's foreseen a relationship with them, and the person eventually gives Grindelwald whatever he wants. When he decides he wants his captive, the President's right hand man on his knees for him, Grindelwald's sure it'll be simple. Only Graves laughs in his face and shows no sign of relenting over time. Determined, Grindelwald decided to work at seducing the director, as long and as hard as it takes.