That's rather offensive, Dennis. It's pretty damned sad when Christians are all lumped together with the extremists in what is a very large diverse group.
To me, as a Christian, being called a "Bible thumper" is a pejorative, along the lines of calling a Moslem the "R" word or a Jew the "K" word.
None of these designations should be acceptable, even if the three groups involved have elements in them that are undesirable at times to others (and even to those in said groups, if truth be told).
Even if one disagrees with another person's religious leanings (or lack thereof), it's only common decency to avoid stereotyping.