Andrew Gelman notes that even writers on the religious site Beliefnet are using “religion” as a term of insult. http://www.stat.columbia.edu/~cook/movabletype/archives/2010/01/climate_change_1.html#comments
“I encountered an extreme example of this sort of thing recently, from columnist Rod Dreher, who writes disapprovingly of "(Climate) science as religion"--on a religious website called Beliefnet (which has, under the heading, "My Faith," the options Christianity, Buddhism, Catholic, Hinduism, Mormon, Judaism, Islam, Holistic, and Angels. Dreher actually appears to be a supporter of climate science here; he's criticizing a dissent-suppressing attitude that he sees, not the actual work that's being done by the scientists in the field.”
I don’t think this use of “religion” is new, although it may be more common.
There is a similar pejorative use of mathematical arguments as being divorced from reality (remember W dismissing Gore in the debates as “fuzzy math”). As William Thurston wrote at the time, “I gradually came to understand that by ''fuzzy math'' Mr. Bush meant, ''Math is confusing and fuzzy, so ignore it.''”. http://www.nytimes.com/2000/10/06/opinion/l-bush-vs-gore-debate-aftermath-fuzzy-math-520543.html?pagewanted=1
There is a similar dismissal of scientific arguments extended beyond the immediate evidence, notably in Mark Twain’s famous passage:
“In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oolitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”
- Life on the Mississippi
Similarly, arguments can be undermined by being called either “fashionable” or “old-fashioned”.
In fact, a reasonable hypothesis is that nearly anything can be used as a term of insult if you try hard enough. But perhaps that’s just an ivory tower notion.