I think the ADL falls well short of expectations on a logical, intellectual level. The ADL’s arguments are a bunch of straw-men.
For a comparison, let’s try this: Is supporting a “Mahatma Gandhi candidate”, a “Shimon Perez candidate”, or a “Dr. MLK Jr. candidate” exclusionary towards non-Hindus, non-Jews, and non-Christians, respectively? Of course not. I as a Christian can readily identify with many of the values promoted by the late Gandhi and the late Perez, and I would feel much sympathy towards a politician following their values and ideals today. Likewise, many non-Christians feel great respect and approval for all those moral values promoted by Jesus Christ and Dr. Martin Luther King Jr., respectively, and thus they do welcome “Jesus candidates” and “Dr. MLK Jr. candidates” whose political platform is built on the same moral values represented by Jesus Christ and by Dr. MLK Jr.
Also, candidate Rick Santorum clearly stands for such moral values taught to us by Jesus, like adherence to the Ten Commandments (Thou shalt not kill! - including as in abortion) and re-uniting and serving all of America, which flows from the great commandment of “Love your neighbor as yourself”. These moral values clearly have legitimacy in the marketplace of ideas, and it would be an offense against Christians’ First Amendment rights to censor these ideas just because they can be prominently linked to the person of Jesus. In addition, the same ideas are upheld by many well-meaning agnostics, atheists, Muslims, and Jews, thus we may yet see a number of agnostic, traditional (Torah) Jewish, and Muslim people supporting the “Jesus candidate”.