Maybe she was looking for something like Unitarianism but with more structure and discipline. It's hard to say what happens when Theresa goes to a mosque and meets Muslims from a different background. Maybe there's a whole mosque somewhere filled with people like her.
Female genital mutilation goes back to pre-Islamic times in Africa. There's no denying that it's become accepted in the Islamic world, but strictly speaking it's not mandated by the religion itself though many Muslims and non-Muslims make that assumption.
And more exotic and more alien to whitebread WASP types. She's basically using her religion like an extreme piercing or body modification.