Franzl is right. Even though in the 1960's and 70's when these accusations were made I wouldn't be surprised to see a majority of whites to agree with them.
There is no basis whatsoever that "many" Americans agree with these accusations (especially today).
But Phil...."many" is relative. Imagine how many people supported Joseph McCarthy's crusades...just as an example of how crazy some people can get.
You could ask: "Do you believe Barack Obama will ban Christianity?", and you'd get 10%+ who would answer YES.