Willow did not do that. They did not have sex that night. Tara cuddled up to her but that was it
Actually, we don't know. We do know that they got cuddly and Tara was forced to behave as though nothing she was angry over happened.
She was turned into a Willow plaything, a mindless and obedient puppet whose anger and feelings were erased -
Willow's will be done whenever inconvenient.
Tara had her ability to consent to any aspect of their interaction removed.
How is this different from what Warren did to his actual girlfriend with that magic gem? I guess Willow did not share Tara with anyone...
Tara's agency and personhood was stolen so Willow could erase their fights and get her "preferred" version of Tara - one who is compliant with Willow's will and ready to be 'friendly' instead of angry. She wanted a human teddy bear!
That is soul rape.
This is particularly perncious after Glory stole her mind. This is in addition to how her family, by their lifelong abuse, stole her agency (her right to decide for herself and to live as she saw fit as a full person).
And any time in future that Willow and Tara did have sex it was sex under false pretenses because she did not know - could NEVER KNOW - whether she would give consent to ANY part of the relationship - she did not know all of Willow's actions. (their whole relationship could be said to be fruit of a poisonous tree... Her actions are shaped by her reality after Willow's spells and conditioned on her false perception
If someone had done what she did and tampered with my brain, magically or chemically, it would take an extraordinary set of circumstances for me to be with that person ever - mentally, emotionally or sexually. Even as a friend.
This violation goes beyond forcible rape into a realm of control that is terrifying. It was essentially like being roofied so her mind could not hold the memories that would be necessary for consent to ANYTHING. She was making Tara into her "April" (the robot girlfriend)
Sex would be way wrong. But it goes way past sex.
Willow was programming Tara into a puppet who did what Willow wanted - each time she used the spell, she deleted some of Tara's history and therefore her ability to give informed consent to
any aspect of the relationship.
It was clear (from Dawn's comments and Tara finding Lethe's Bramble under her pillow) that Willow did the spell several times, possibly many times.
Tara was living in
Willow's reality, not the actual real world. I wonder how many tests she did not do well on as a result of forgetting what she had studied or learned that day?
That Tara chose to forgive is a function of Tara's heart and maybe a bit about her history of abuse, which would tend to condition her to accept mistreatment.