Why do some people blame modern day Christianity and religion?

The crusades and inquisitions were catholic, not Christian. In fact, many true Christians were the victims because they were thought of as heretics for not going along with the Catholic dogma. Apart from skewing Christian doctrine beyond all recognition, I think God will be especially hard on that organisation because it carried out those atrocities in God's name and tarnished it all over the world. What's worse is that since they brought in this lie that the pope is infallible, it means they can't admit to mistakes. That means they can't repent. So those things are still hanging over their heads. You can't be forgiven by God if you're not willing to admit you can make mistakes.