Inspiration is one thing, plagiarism quite another, which is why the former is generally admired, the latter condemned. To openly weave another's ideas subtley and cleverly into a new form - whether in music, art, literature, engineering, computer-programming ... - is an achievement to be proud of; copying it wholesale and passing it off as one's own is not, and, as gm_food justly observes, is unlikely ever to constitute art that everybody could believe in.
If Damien Hirst had had the intellectual (and moral) honesty to own up to copying a children's toy without the threat of prosecution and exposure hanging over his head, the ultimate reaction of public and critics might have been different. Unwittingly, admirers praised the clever way that the sculpture 'Hymn' stripped away the layers of the human anatomy to reveal man's inner workings, vulnerability, mortality. And so they applauded the insight, inspiration, creativity, originality of the man who had executed this 'profound' vision. But it turned out that the artist's only creative and imaginative contribution to the piece was to make it very big, and to borrow a punning title from an old Pretenders song: all the clever stuff, the design, the proportions, the anatomical research, the primary colours, had been done by Norman Emms years before. Many people who had hitherto defended Hirst, or given him the benefit of the doubt after previous outings of similarly dubious merit had finally to admit what others had been saying all along: the Emperor has no new clothes and Damien Hirst is a fraud.
Like so much that is produced today for mass consumption, the work of Hirst, Emin, et al. is entirely disposable and forgettable: even its less shallow observations have already been dealt with by more insightful and adept 20th Century artists, from Marinetti to Warhol, and to keep retreading the same old ground is really rather lazy and dull. But there may be nothing wrong with that, as long as everybody, most of all, the 'artists', is honest enough to admit it.