Again you are talking about a minority. There are bad people in any walk of life, this is a fact of life. And yes, Christians have done many evils, but they have done many good things. When the Spanish came to central America, some Christians demanded that the natives be treated better than what they were. The same evils can be extended towards money, race, land and resources, and even love have driven people to cause horrendous acts and go to war.
Religion is abstract and open for interpretation. Most people will not act any differently because of it, a few will be good people because of it, and a few people will be bad because of it. Such data will always show a slope (bell curve), with an average and the numbers will slope in both directions. Even Glen Beck's audience falls under this. Most people don't take him very seriously or just see him as another news/opinion TV persona, a few people take him seriously, and Glen Beck has inspired at least one person towards violence. Every group has their black sheep, and to discredit the entire group for the minority of bad apples in that group is unfair.