Seriously? They are reptiles not animals? Not sure where you got your degree in zoology, but mine was from Michigan State University and all the way back to Linnaeus they were still animals. Though he was small minded and thought of them as lesser creatures. I'm absolutely flabbergasted by that response... But to break it down Barney style for ya:
Animals are anything from the Kingdom Animalia, characterized as being multicellular eukaryotes. That would be both Reptiles and Mammals along with most other mobile organisms you are likely to run into. What in your opinion is an "animal"? Only mammals?
As far as "far from endangered" the roundups themselves have noticed a decline in populations of these snakes. The Eastern Diamondback has been in steady decline, probably since the settling of North America by Europeans, but it has been exacerbated by Roundups.
Eastern Diamondback Rattlesnake Closer to Endangered Species Act Protection
Here is a good white paper on the effects of these roundups on wild populations and the roundups themselves.
http://onemoregeneration.org/wp-content/uploads/2010/11/2009_MEANS_Roundup_Effects_paper-2.pdf
Timber Rattlesnakes are endangered in 6 states and threatened in 5 more, including Texas. The reduction in Eastern Diamondbacks has been correlated with an increase in the rabbit population.
"One of the penalties of an ecological education is that one lives alone in a world of wounds. Much of the damage inflicted on land is quite invisible to laymen. An ecologist must either harden his shell and make believe that the consequences of science are none of his business, or he must be the doctor who sees the marks of death in a community that believes itself well and does not want to be told otherwise.”
― Aldo Leopold, A Sand County Almanac