My friend told her mom that she had sex and now her parents won't let her leave the house?

I know i can't do anything, but do you think they're overreacting or not? She had sex (she's 17) with her boyfriend. They had been going out for about 10months. She started to get worried, so she told her mom that she was sexually active and would like to get the pill and her mom flipped out on her. Her mom told me that I wasn't allowed over to her house anymore because I'm a bad influence (which doesn't make sense because I'm a virgin, and i honestly don't drink, smoke, or anything that would make me a bad influence.)

They banned her boyfriend from seeing her, took away her phone and her car, and won't even look at her. I was there when they were freaking out on her and her dad threw a pickle jar at her and called her a slut. I don't get it! They've never acted like this before she said. She was expecting them do be really accepting, maybe a bit shocked, but she thought they would be idk happy she was trying to be responsible. I only see her at school now. Idk, what do you think? i think this is why a lot of girls don't ask for the pill.....

(P.S- they're not really religious or anything...sooo)