Yes, but Dinosauria are not reptiles and Owen had no idea that Birds were Dinosauria.
No, it’s not nutbag stuff. Honestly there are reputable scientist who argue that altho Aves and Dinosauria have a common ancestor, they split off before.
Background
Main articles: feathered dinosaurs and origin of bird flight
A minority of scientists prefer the hypothesis that birds evolved from small, arboreal archosaurs like Longisquama. They see these as ectothermic animals that adapted to gliding by developing elongated scales and then pennaceous feathers. This hypothesis, however, is not supported by cladistic analysis.*
https://answers.yahoo.com/question/index?qid=20140525120521AAVvzTQ
*There is no consensus. Most paleontologists are cladists, and practically all cladists believe that birds evolved from a dinosaur. There are also many biologists who have not kept up with the latest research on bird origins, and they were taught as undergraduates that birds evolved from a dinosaur similar to Deinonychus if they received their university education since the late 1960s. These 2 groups add up to over 50% of scientists. Starting in the mid-1990s, however, more and more scientists now doubt that birds evolved from a dinosaur. It started with developmental evidence by scientists such as Richard Hinchliffe, who found that birds most likely had fingers 2-3-4 but fossil evidence strongly suggests that theropod dinosaurs have fingers 1-2-3. Then scientists like John Ruben, Alan Feduccia, and Larry Martin did research that show that the taxonomic characters uniting theropod dinosaurs and birds are extremely unlikely to be homologous, suggesting instead that they are only superficially similar. Then, in 2000, a paper based on the re-examination of the fossil Longisquama, which was part of the group of fossils being brought to the USA from Russia, shows that it has feathers that were likely homologous with those of birds. Since Longisquama is not a dinosaur by any stretch of the definition or the imagination, it dealt a severe blow to the view that birds evolved from a dinosaur.
Knowing that Longisquama feathers would deal their cladistic religion and their careers a severe blow, because they would have to admit that cladistic analysis failed time after time to come up with the correct answer about the real ancestor of birds, some paleontologists tried to bury the facts. … That is not all, the cladists are spending time courting the popular press and ignorant journalists to continue propping up the theory that birds evolved from a dinosaur.
The facts simply do not support the dinosaurian origin of birds, because there is no known fossil that has the features of Deinonychus and that lived in a period of time before the oldest known birds. …Of course, cladists once again deny this piece of evidence, as they had done to all other pieces of evidence that contradict the dinosaurian origin of birds.
So, in short, if a paleontologist’s career or career opportunity is dependent on adhering to the largely refuted dinosaurian origin of birds, then he/she probably has little choice but to keep on pretending that birds evolved from a dinosaur and bury both the facts and his/her own integrity. OTOH, scientists who are interested solely in a better understanding of nature are joining the small but growing number of real scientists who have abandoned the dinosaurian origin of birds.*
*CORVALLIS, Ore. - A new study just published in the Proceedings of the National Academy of Sciences provides yet more evidence that birds did not descend from ground-dwelling theropod dinosaurs, experts say, and continues to challenge decades of accepted theories about the evolution of flight.
A new analysis was done of an unusual fossil specimen discovered in 2003 called “microraptor,” in which three-dimensional models were used to study its possible flight potential, and it concluded this small, feathered species must have been a “glider” that came down from trees. The research is well done and consistent with a string of studies in recent years that pose increasing challenge to the birds-from-dinosaurs theory, said John Ruben, a professor of zoology at Oregon State University who authored a commentary in PNAS on the new research.
The weight of the evidence is now suggesting that not only did birds not descend from dinosaurs, Ruben said, but that some species now believed to be dinosaurs may have descended from birds.*
https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.10382
http://archive.news.ku.edu/2000/00N/JuneNews/June23/dino.html
Those guys are not, in “nutbag flat-earther territory”. They are experts- which you are not.