Dinosaurs were obviously related to reptiles, and the early reconstructions reflected this. Reptiles are cold blooded, therefore dinosaurs must have been cold blooded. Reptiles walk with splayed legs, therefore dinosaurs must have walked with splayed legs. Reptiles drag their tails so therefore dinosaurs must have dragged their tails.
Not all early paleontologists accepted that dinosaurs were slow-moving, cold-blooded critters (more creationist misinformation). Some reconstructions from the 1920s and 30s show very active dinosaurs. These paleontologists noted that extent dinosaur tracks showed the animals with legs under their bodies and lacked any tail marks. Recent analysis of dinosaur bones show that most were at least semi-warm blooded (bones of warm-blooded animals are very vascular; dinosaur bones fall between the ranges of warm-blooded and cold-blooded animals).
Creationists are always mired in their personal pasts. "Thirty years ago, such-and-such was taught, and now we're told something different, therfore it's all wrong and no one knows what he or she's talking about." Creationists never make allowances for advances in science (except when it reinforces a personal position, such as global warming). Of course, science marches on despite the braying nay-sayers.
OTOH, Bill Watterson--the creator of Calvin and Hobbes wrote in one of his books that he first drew the dinosaurs in Calvin's fantasies based on his childhood recollections of scientific descriptions of dinosaurs.
He was pretty surprised to find out that the accepted description of dinosaurs had drastically changed by the time he grew up and started the strip.
I suspect the difficulty elucidated by the poster you are here responding to, is the apparent contradiction between the ex cathedra pronouncements of evolution as absolute, unquestioned fact, and the revisions in consensus among scientists over time. Another such revision (in the popular mind) can be seen by looking at the section of Disney's Fantasia based upon Stravinski's The Rites of Spring in which the death of the dinosaurs was portrayed as due to rising global temperatures and drought, as opposed to (say) impact of earth by an Iridium-rich meteor...
Recall most lay people don't get as far as peer-review journals, or even Dawkins or Gould. Disney or Time Magazine is as far as they get.
Ah, but it's not the rosey picture you paint, is it. The thought that dinosaurs could move at warm blooded paces and therefore be warm blooded was the notion of a very few in the community and was accepted only after the evidence for it went public. Once the evidence was public and near incontestible, then things changed. But it was a long time coming and with great resistance. The community is not the fluid organism you describe. It is ICE which thaws every once in a while to take another form only after someone boils the cube and ticks a lot of people off by showing they aren't as smart as they thought. There are too many egos involved who think themselves too smart to be wrong. Seems to be common amongst certain types for what that's worth.
Some evolutionists demonstrate a penchant for hyperbole.