Early on, the protagonist begins to explain that she doesn’t look at men – they scare her. Instead, she looks at women. Women are the only people who have ever been kind to her. Her sexual identity becomes that of a woman who loves a woman. In this novel, sexuality isn’t about loving one gender or the other, it’s about loving individual people. In the protagonist’s case, she loves a woman.
The Color Purple indicates that love has nothing to do with a person’s sexual identity. Love happens where it happens and nobody can predict it or stop it.