They are wrong, but they're not evil.
Many Atheists I know often call religious people, particularly those who proselytize and preach, evil. It appears that anyone who wants to keep marriage away from the gays, and get creationism taught in schools is evil, but 99% are not. Yes the consequences of their actions could be termed "evil", but at heart, the causative agent is not evil.
The simple fact is, is that they are just trying to do what they think is right. If you ask any Christian what they are trying to achieve for humanity by preaching whatever they do, you'll find its things like "everyone should love each-other", "everyone should be happy", "no one should be suffering through poverty", etc. These are quite similar to secular goals, except religious people have a different way of trying to achieve them.
The way they are trying to achieve them might be wrong, but a positive outcome is still what they are trying to do. No one can hold such incorrect beliefs so firmly if the beliefs weren't leading that person towards a more ultimate purpose. They are not evil, they are trying to achieve the exact same thing many of us are.
The way to solve the religious problem is to alert religious people to the common ground we have, in our ultimate goals, and try to educate them on the alternative (secular) way of achieving them. Ignorance is usually all that is holding people from accepting such an obviously more correct view of reality. Attacking them isn't going to change their beliefs, getting them to listen first, and educating them second, is what will make a difference.
By calling the person committing "evil" acts an evil person, it won't convince them to change their position. They know they are not evil at heart, and by calling them evil, you convince them that you must not understand their position, and that you must be "one of Dawkins mindless sheep". Yes they might be committing evil acts, so point out the consequences and call that evil. However your average Joe Blow Christian is good at heart, just misinformed and ignorant, causing "evil" consequences through good intentioned actions.