"Actually, looking at the bones can give an excellent understanding of how they moved."
Up to a point. When I was child all the museums and books protrayed T.Rex and his close relatives as Godzilla-type creatures, standing up, quite improbably on their hind legs. Now they are pictured as carrying themselves much more like birds, with tail out behind and neck and head forward.
"Sure; but they don't, contrary to anti-evo belief, just make it up out of thin air."
They extrapolate so far from so little that they might almost as well. But of course those shows are not science, they're entertainment.
Of course, all of the 'true believers' hang on every word.
That's because new, better information has been discovered. Do you think there should be NO speculation on these issues until there is 100% certainty? The new, better information, and new, better speculation came from scientists doing science. That's the way science works. Nobody claims that science gets it 100% right the first time - it's a process of iteration, and moving closer to the truth. Can you think of a better approach to discovering natural truths?