Is it wrong that I'm thinking of not letting my daughter attend her friend's church?
Why do you want to stop her from going?
I don't want my daughter to be brainwashed. Most religions are like cults.
Not wanting your daughter to attend her friends church is understandable if you aren't a fan of religions, but you shouldn't just go around insulting religion like that. It's extremely rude so I hope you try to avoid that in the future.
Why should I? I'm entitled to my opinion and I think it's wrong to brainwash kids into loving a false god.
You can have religious preferences. You need to look into different religions and decide what's best for you and your family. You might end up liking one better than other so not all religions are bad.